Some escorts seem to get more reviews than others, even if they aren't getting more clients. There are some patterns I've noticed. Mature escorts tend to get fewer reviews, as do BBW's, black escorts and fetish or BDSM escorts. But there are exceptions, I'm sure. Some of it just seems random. So I don't think you can assume that no reviews means she's not busy. As to why she doesn't do outcalls, for many escorts it's a question of safety.