Yes, the majority of outcalls definitely do take place at hotels. That said, I have also been to numerous gentlemen's homes and apartments for outcalls.
Outcalls to a home require a great deal of trust from both sides. The client is taking a big risk by allowing a complete stranger into his home - someone who may have less than honourable intentions, may steal, snoop, bring along a pimp/friend/driver, keep records of personal information, etc. The escort takes a big risk with her personal safety, visiting a lone, unknown man in his own domain is always a scary proposition.
I always feel safer in a hotel because it is neutral and "public" territory, but depending on the vibe I get from someone, I may be willing to visit him at home. I will not, however, visit someone in their own home without knowing their true identity. So, they have to be willing to provide their real name (which I usually match up to the phone number and address on canada411.com), which of course increases the risk to the client.
So yeah, the trust has to go both ways. For the guys, it's best to stick with girls who have a reputation to uphold. A girl is less likely to rip you off or cause trouble if she knows her reputation and career are on the line. For the girls, make sure you have a buddy system in place when you visit a guy at home.