Been looking at the feedback on mask policies from two separate conferences. People seem to fall into three groups:

1) I'll go with the policy, whatever it is

2) The risk of attending an event without masks is too high, so I will not attend without a strong mask policy

3) You cannot force me to wear a mask, so I will not attend if you require them.

You can always get group 1 at your con. Choose between groups 2 and 3.

My random sampling says that group 2 is nicer than group 3. Group 2 is both easier to hang around with, and safer.

Easy choice.