All spas have cameras, at least all erotic spas. Get used to that. They may film the front and back entrances, anywhere they store cash, and the hallways to the shower and rooms. They are NEVER and I repeat NEVER in the rooms, and can not see in the rooms. There may be some rouge dudes out there who put spy cams in the ceiling, but they are RARE and usually get caught and you see them on the news.
As for writing your name down, I can see that as a safety measure on their part, it may discourage robbery if you have to ID yourself to get in, it certainly should discourage anyone from acting up or getting violent with the ladies, it also ads a bit of legitimacy to the business if they keep an appointment book.