Gen Con said this year's turnstile was about a four percent increase. Let'ca call it 210K. 

Let's assume your 75k unique attendance estimate is correct.  If the first 60K people had the identical number of four day and single day badges as in 2016, there's no way an additional 15K of attendees could raise the turnstile only 4 percent. Even if all 15K bought a single day badge, that would still result in a turnstile increase of over seven percent (15K/210K).

So the only way turnstile could only increase 4% iwhile increasing unique attendees 25% would be as Parody mentioned: you'd need to see a big decrease in four day badge sales compared to 2016. But you already rejected that scenario with your "monkeys flying out of your butt" comment.

You can't be right on both counts, and are probably wrong on both.
I think you're also wrong about how turnstile is calculated. I think it's  done solely on the badges sold. I've never heard a Gen Con Official say turnstile is calculated not how many times people are going in and out if the building. 

Yea, the numbers look wacky 52,000 4 day badges gives you the 208,000 turnstile, that number just does not look like a sell out number to me.  Then 10,000 single day badges to get you to 62,000 badges, 18,000 to 70,000, which is only 4,500 average single day badges.  We will never know the breakdown. 

1. Every badge sold is a "unique attendee."

2. Every 1 day badge is 1 "turnstile attendee." (Including extra names entered on Sunday Family Fun Day badges).

3. Every 4 day badge is 4 "turnstile attendees."

Then it's simple:

x is the number of one day badges sold
y is the number of four day badges sold

u is the number of unique attendees
t is the number of turnstile attendees

then:

x+y = u
x+4y = t

And since we know u and t, we can calculate x and y:
y = (t-u)/3
x = (4u-t)/3

2017: Turnstile 207,979, Unique "approximately 60,000".  I'm going to assume the unique attendance was less than 60,819 because "approximately 60,000" sounds a lot better than "two consecutive years of declining unique attendance."  Let's call it 60,000.
http://www.gencon.com/press/gencon50

2016: Turnstile 201,852, Unique 60,819
http://www.gencon.com/press/postshowrelease

2015: Turnstile 197,695, Unique 61,423
http://www.gencon.com/press/2015postshow

Badge breakdown under these assumptions:

Year - 4 day - 1 day 
2017 - 49,326 - 10,673
2016 - 47,011 - 13,808
2015 - 45,421 - 15,999

There were not 75,000 unique attendees.  With all due respect to Frank Mentzer, he's not a Gen Con employee and there is no reason to think he would have attendance information that contradicts what Gen Con themselves posted in their press release.  It is implausible that Gen Con would not have mentioned a record setting unique attendance figure if it had happened.

As a demo agent for catalyst I can tell you there were DEFINITELY clickers counting each of the four doors that were directly in front of the catalyst booth and they did so each and every day including Sunday. We even heard the instructions. However...I don't think they continued clicking after the first twenty minutes or so. Then again by then I was busy and my attention elsewhere. 

When they first opened the doors they had folks counting one per door. One click per person. I will also day this was my first year seeing the mass of humanity from the INSIDE and it was pretty something. What I really didn't see though we're people running. 

I also found an article that had unique attendance at 75000 for some religious convention a few years ago. They too complained about hotel overflow to the suburbs and beyond. So I don't see how max attendance could be 60,000 from a fire marshal standpoint.

But remember the fire Marshall cap isn't just attendees but also gencon staff, convention center staff, volunteers and all the dealer hall people.  As for clickers I didn't see any for vig early access or any other time I went in the dealers hall.  But then I avoid the first hour or so and go in around noon.

I certainly do not know that my hypothesis is true.  But, I think the fact that they have not released a unique visitor count this year (despite doing so in previous years) could mean that.  It could also be your explanation.  But, Gen Con has had attendance declines in the past.  Something like 8 times in the past 20 years.  This feels different.

I believe all of our questions can be solved by using... wait for it...

A Random Number Generator!!!!

2017 Unique Attendance = 58006 (Used 55K-65K)

All hail RNG!

The only 'fact' anyone has here is that they do not know and are guessing.  I've seen sources, far more credible than anyone here, put the number over 70k.  Anyone trying to say turnstile attendance answers the question has no idea what they are talking about.  There is no static correlation between badges sold and turnstile numbers since no one knows how many one day vs four day passes sold or how many times those people went into, out of, and back into the hall.

You also mistakenly believe badges sold has a static correlation to turnstile numbers.  It doesn't.  You do not know how many times each person went in and out and we have verified, via multiple people here, they were counting.  I've been to the con many times, hell I worked it when I worked at WotC, and I've always seen people at the door with count clickers.  Additionally, if unique attendees DID correlate to a static turnstile number the unique attendees and turnstile numbers for each year would have an easily discernible mathematical formula that would result in an exact, predictable number between the two each year... which is not the case.

Okay, no need to start doing point-by-point posts - that way lies madness.

And remember to keep it civil. 

Roderick Robertson
Forum Coordinator 
Gen Con, LLC. 

Given that:
a. Gen Con announced the exact record setting turnstile attendance in 2017
b. Gen Con has announced exact unique attendance records for years when it was record setting (2015)
c. Over 70,000 unique attendees would have not only been record setting, but exceeded the prior record by over 10%

It is completely implausible that there were over 70,000 attendees and yet Gen Con is lying to the public in their press releases and passing up the opportunity to market a new record.

What are your "far more credible sources" than Gen Con's own press releases that the actual number was over 70,000?
 

My point is only this:

Some people seem to be advocating a position similar to: "The 4 day badge sell out of Gen Con was because attendance had reached the maximum safe amount, and further attendees would have caused safety concerns and possibly resulted in intervention by civic authorities such as the fire marshal."  This position may briefly be expressed as "attendance was the sole reason why 4 day badges sold out."

My point is that that position can not be correct, as there was a point in time where 4-day badges were sold out, but badges for any individual day were available.  

This demonstrates that Gen Con did not believe at the time they stopped selling 4 day badges that attendance on any given day had reached a maximum safe amount, and that further attendees an any given day would cause safety concerns and result in intervention by the fire marshal.

Your idea that:

"It's pretty common sense that there was likely a daily cap that was a combined number of four and single day badges.  When they hit the cap for four day badges they stopped selling them and people then had to buy single day badges, for whatever days those were still available."

Is, I think, pretty much correct.  The implication of that is that Gen Con stopped selling 4 day badges because they had some preferred mix of 4 and 1 day badges, not because selling further 4 day badges would have jeopardized attendee safety or resulted in being shut down by the fire marshal.

I wonder when the next 'gen con should move now that we have capped' post will happen!

____________________________________________________
Alec Usticke, Unofficial Gen Con Indy Facebook Discussion Group

I'd hate it if they only went to single day badges..

How much does a single-day badge cost?  Because I only really use three days.  I'm too tired by Sunday to do anything worthwhile.  The most i ever do is stroll the exhibit area a bit