I allow models/performers to bring someone with them to any of my projects if it makes them feel more comfortable.
I do this in part because I have heard too many stories from models about creepy photographers that only want to get girls alone to see how much they (the photographer) can get away with groping the model, asking them to go beyond their limits, or even propositioning them for sex.
My sets generally have a small crew of people consisting of a Make-Up Artist, 1-2 Production Assistants, a Still Photographer (doubles on video), and Videographer (moi). For hardcore shoots, I generally add another video shooter.
If you look at most mainstream productions, and the better adult productions, they all have a good sized crew. Some even have audiences.
Granted, I do not shoot extreme content (no anal, etc), and I never intend to shoot anything outside what we have already discussed during the storyboard/scenario review.
Most often lately, girls will bring another girl to the shoot. Sometimes I end up with a new model (lol). When they bring a guy, it's generally a friend, and not significant other. Even when it has been a BF or hubby, I have never had a major problem. I've even had a few BFs become PA's.
When there are girl escorts, quite often they help out with wardrobe/make-up. I sometimes put the guys to work manning a camera on a tripod.
I've been shooting professionally for over ten years, and I figured out how to deal with model escorts early on. First, you try to get a quick sense about the relationship and the personalities. Either put them at ease (I provide food and non-alcoholic beverages), or take charge and direct - where they will be sitting (out of the line of the sight of the model), when they can speak, etc.
Frequently, as we are doing the paperwork, either the model or escort will ask where the escort can wait, since often they do not wish to watch, but merely came by because the person needed a ride, or to ensure the environment seemed safe.
As for hardcore, most of the girls whom I hire are already in the industry, and they no longer have escort issues. Those that aren't generally work with their BF/hubby or are fine working with someone that is tested, once they are clear on exactly what we will be shooting.
The simple fact is, this is not flipping burgers. When a BF/hubby/father drops their girl off at Mickey D's for a shit, they are not expecting that she will be throat-gagged/spit-on/sodomized, etc. Not all jobs are the same.
Unfortunately, there are some in this industry that have misogynistic attitudes, and their business is built around degrading girls. It is obvious why they would want unescorted girls.
What content producers need to do is quit lying to, trying to trick, and stop abusing girls, and maybe more girls will want to be in this industry.
ADG