I think a lot of prostitutes are afraid to file complaint when they are raped because of their illegal profession. I guess they might think that its like someone doing drugs reporting that their cocaine was stolen. Still, I would think a fine for solicitation would be worth it as opposed to letting a brutal rapist go free.
I also wonder how seriously police take prostitute rape claims? In interviews with prostitutes, it seems like they suffer rape a lot, but you rarely hear the story about the prostitute pressing charges