At most hair shows (which are generally in conjunction with a convention for hair stylist related products), there are four different areas that models may be hired for.
The first are the models that they use to demonstrate cut and style (and/or coloring) techniques with. This is done all day, generally, throughout the show and girls are shuffled in one after another. This can be fun for someone starting out and can produce some cool new looks for the girls. At the last one I attended, there was one guy cutting like he was Edward Sissorhands. It was a sight to see and very entertaining (but I'd never let any of my girls go through that because of the drastic changes and how it would affect them on their regular print jobs).
In fact, this is the guy that was just slashing away like Johnny Depp (Sissorhands)
The second are models used for runway shows. These are usually pure entertainment and to catch the audience attention. Sometimes they consist of girls who've been through number one, above. These are pretty much as you'd expect with the models walking the runway, the music blaring, and often an announcer:
Then there are what I'd refer to as "booth girls." This is generally where I don't mind having girls placed - and it pays very well, usually. We had several girls hired by Jessica Simpson for her new hair-extensions line... and the models left with over $1000 in extensions and pieces to keep (once they wear them, they can't be resold, etc.). Our girls loved this because they have wonderful hair pieces now to use for shoots, jobs, etc. Photo is two of our girls who worked for Jessica Simpson at the last show in Texas. (THESE ARE HAIR EXTENSIONS THE GIRLS ARE WEARING)
Finally, there are pre-show promotionals... for instance, the one below that is one of our girls on FOX TV. Marc Anthony was in town for a show and hired her for a short demo on the morning news.
The shows are actually a lot of fun to attend. Lots going on, great products, demonstrations, and just a really cool feel about them.