(Before continuing, I'll stipulate that in some areas, there are "ticket taxes" and that convention memberships aren't subject to them, but IMO calling our admission prices "memberships" is not a tax dodge and never has intended to be such a thing.)
To me, a "ticket" is something you buy that says you're paying the organizer to entertain you. You buy a ticket to a ball game or a concert or a movie or to the county fair or things like that. They are fundamentally passive, in that you are a consumer and the organizer of the event is a producer. So to me, a "ticket" to a convention-like event is really you saying that you're hiring the event promoter to provide you with a "popular-culture sci-fi entertainment experience," and that the event organizers are contractually obligated to you just like a movie theatre or sports team or concert promoter is. I encountered this attitude lately with someone who insisted that the money he paid for a convention membership must be totally refundable upon demand (unless you said otherwise), and that failure to refund the membership upon demand for any reason whatsoever was fraud.
A "membership" is something you buy to a club or other cooperative society, and the relationship is two way. You're not just purchasing pre-digested, pre-packaged entertainment; you're joining a club in which you're expected to take an active part. Everyone under the roof of the event is a member. Some of them help out by doing the organizing part, but they're not different or special, and they're certainly not "employees" to be treated the way you might treat the wait staff at a restaurant.
This was recently thrust in my face by a discussion about a particular convention where one of the participants referred to one of the organizers as an "employee." As far as I can tell, that person though the people putting on conventions were employed by some company to put on the event for the attendees' entertainment, just as a singer is paid by a concert promoter to entertain the people who bought tickets to listen to the show. The idea that people would actually spend their own time and their own money without being compensated by a salary to put on the kinds of events we typically call "science fiction and fantasy conventions" was a shock.
Folks, I don't know about you, but you couldn't afford to pay me for what I would ask as a convention organizer. At the very least, you would have to match my existing salary as an engineer, which is broadly within the median for technical workers in my market. And if you had to pay all of the people putting on our events (including the panelists), even at minimum wage, you'd probably have to increase the admission ticket price by a significant amount and also significantly reduce the number of things you were putting on. My shorthand for this has been "ten times the cost for one-tenth the content."
One of the reasons I'm leery of the term "ticket" is that I think it's corrosive to the social contract between the people attending, including the people doing the organizing work. It leads to an Us-Vs-Them attitude. Oh, maybe not explicitly, but implicitly it says "There are Conrunners, who are a Breed Apart, and there are Attendees, who have paid for their ticket and expect the Conrunners to service their needs." This is Bad.
Now, I'm not saying that I expect every single attendee to spend 10-20 hours/week working as a convention volunteer. (That's my estimate of the hours I worked on ConJosé, averaged over the seven years of bidding, planning, and post-con wind-down.) But I am saying that it helps everyone if ever single member thinks of what he or she brings to the table and doesn't treat the person behind the desk at registration or the person setting out food in the Con Suite or the person flashing "5 minute" signs at the panelist as some sort of hired lackey.
While I was out for a walk today, I had a "Modest Proposal" moment: We continue to sell convention memberships at the current prices, but we sell "Tickets" for two or three times as much money, with fewer privileges. For a Worldcon, for instance, a ticket might cost $500, and not include any publications, voting rights, or other membership rights — it would just be an admission ticket. And if someone complained at the high ticket prices, you could just say, "Oh, you can buy a membership for a lot less and get more."
I reckon this wouldn't really work, because few people would actually get it, and the negative press you'd get over telling $500 "tickets" would overshadow the real membership costs at a significantly lower price, but it's nice to think about.
Mind you, it could be that I'm just one of those old geezers who has to hurry up and die so that Real Fans can run Proper Conventions without all of those weird old-fashioned notions clogging up the works.