Hi Eido!
The Fetish Fair Fleamarket page that I linked to has a
rules page, and the various program booklets from past Fleas also have rules and etiquette sections (pgs 4-5 in
last year's booklet (pdf)), which might be useful. Contrary to Cutter's experience, they ban photography and video in public spaces, and someone could be escorted from the premises for violating the ban.
Regarding the hotel staff, they're all there, doing their jobs as normal. Everyone goes into the event eyes-open; we're as respectful as possible to the staff, and they're respectful to us. Room service, bars, and restaurants are open (though maybe on more of a "convention meal" schedule than normal day-to-day operation), housekeeping and maintenance make the usual rounds (I imagine they knock *extra* loud, though), hotel security is there in their blazers working with the con staff and con security, concierge services are available, etc.
As far as "vanilla" vendors, the Flea is pretty much all kink or "kink-friendly" -- there are some vendors that sell, like, ren-faire-type clothing, some doing henna or body art, etc., but nothing completely unrelated. Stuff like yoga or dance lessons would be done more on the presentation side of things, with, say, a morning yoga class scheduled in one of the presentation rooms, or an "Intro to Belly Dance" class. But these would be of a volunteer-led basis, not for-profit (*).
Regarding models, at the Flea, at least, the vendor spaces are usually too small to have dedicated models just standing there looking pretty. Since the event is in a hotel convention space and not a full-scale Convention Center, space is at a premium. Most of the vendor spaces are maybe 12'x12' or so, or some vendors will be set up in one of the normal hotel rooms (they set aside a hallway or two for this), so there's maybe room for like 3-4 workers tops, plus all of their merchandise and displays and storage, etc. It can actually get quite crowded if a particular vendor is popular. That said, everyone's friendly and the vendors are usually happy to demo a product or let you try it out (or on).
(* - note that with the Flea, at least, volunteering for a certain number of hours gives you comp'd admission to the rest of the weekend, so people running something like that
do get compensated, just not in a revenue sense.)