This is an issue on which I have very strong opinions.
I believe that every event publicly posted on FT should be open to everyone who wants to come. This openness and sense of inclusion is the very essence of our wonderful community.
Obviously there will be some activities that are necessarily limited by the size of the facility or the number of open reservations, but those can only be handled fairly on a "first come, first served" basis, without prejudice or manipulation of the guest list.
If there are any restrictions whatsoever on an event other than the size of the facility or number of available seats, the organizer should not post it on FlyerTalk, but should handle the entire event by private e-mail. I think this should apply if there is even one person who the organizer wants to exclude from attendance. If you really dislike someone that much, just stay away from them. I rarely even have time at FlyerTalk events to talk to the people I really do like, let alone the ones I don't like.
We are very blessed to be a part of this community and we are a part of it only because each and every one of us was at one point welcomed in with open arms. The only way we can preserve what we have is to continue our tradition of openeess.