Truthfully any mask mandate is more of a symbolic gesture than anything else.
I just don't see how you enforce a mask mandate effectively through the whole convention space. Hotels are unenforceable besides in the meeting room that gencon booked. The convention center is pretty much unenforceable in any of the hallways since they don't check badges to enter the convention center. Don't expect your server at a restaurant or anyone around you at the restaurant to be wearing a mask. Don't expect your uber or Lyft driver to be wearing a mask.
This convention is in a heavily red state that lifted the mask mandate a long time ago. So trying to enforce one during Gencon is going to be like putting a square peg in a round hole.
I am not even against having to wear a mask. But if you are attending you should expect a good chunk of exposure to maskless people no matter what Gencon decides.