The Fans of Gen Con Facebook page currently has a poll on this subject. The question was:
If an event had in its info "We ask that you please mask while attending this event for the safety of our immunocompromised staff/performer(s)"
What would you do?
600 people responded. Current totals are:
Yes, I would make sure to be masked - 474 (79%)
Yes, but it would help if the event provided masks because I won’t have one - 45 (7.5%)
No, I would not attend if asked - 70 (11.67%)
No, I would attend but probably not mask - 11 (1.8%)
600 is a really good sample size for this convention. I think the concerns of mass chaos, players being ostracized, and GMs suddenly cancelling events is overblown.
That was a public poll and limited to facebook users, so there's some bias to it.
But based on that sample the only real issue is with that 1.8% group, and even then it's only if the GM or other players take offense in some form, which is likely less than half the time. So really maybe 1% of the population would be problematic if EOs were allowed to request masking. Honestly think GenCon has more to gain (via goodwill to EOs and more GMs probably) from making it an option and filterable in event catalog than lose (via the 1% grumpy attendees) but we'll see.