Thank you, I was about to say that. They aren't required to be fully checked before every movie. Hell, I am sure some of the cheapass production companies couldn't care less. A lot of them don't use condoms, and go on the words of what the *actors* say.
Thus being said, it is an industry. A very profitable one at that. Look at all the strippers who put themselves through college without loans (or just live a very comfortable lifestyle) by pulling down $1,000+ per night stripping.
If you are going to do it, just be safe. It's not for me but I'm not gonna knock someone who wants to use their body to make a little cash- it's their choice. I think it's rather humiliating, but it doesn't matter what I think.