A sincere thank you to the kindly fellow who ran through the ICC with my twelve year old son's badge to return it after he had left it in the bathroom by accident. I did not catch your name, but you saved the con for the two of us, as we would have both had to miss the rest of Saturday and all of Sunday's events since he is too young to leave alone and, of course, badges were sold out. I know I thanked you before when you returned the badge at the "Oh Gnome, You Don't!" life sized board game, but it bears repeating in public! How fortunate we were that you happened to hear me call his name, noticed the unattended badge a moment later, and put two and two together.
And a second sincere thank you to the selfless guy who gave me a ticket to the True Dungeon event on Saturday night that my two sons were registered for so we could all run it together. You and your fellows were awesome!
Just so you know in case it happens again - I'm pretty sure you are able to replace a lost or stolen badge but you have to pay full cost to do so. Believe that particular topic was discussed somewhere else in the forums - though you have to go back to a date prior to the start of the Con. In your case, you aren't buying a badge - you're paying full price to replace a badge you already bought.
I assume you pay full price, because Gen Con LLC doesn't have any way of knowing if you actually just handed it to someone else (i.e. they can't tell if you are committing fraud). Is this a loophole, yeah; but its a loophole that doesn't lose money even if it does add to the number of attendees at the Con. :)