Those scenes where there's a guy whipping out cash in front of the camera, offering her money, talking about this scene or opportunity that he has for her for x amount of money, is scripted. None of that is real. How good do you think your chances would be if you walked into a restaurant, approached some random hot girl, and offered her some money to fuck you? Ok, the girls are chosen beforehand, everything is discussed beforehand, there is almost always a pre-planned "script". Though I don't like to call them scripts, as they aren't usually written down, they're simply discussed.
Sure, in a way, yes, new girls are somewhat taken advantage of. They aren't completely aware of how the business works, and they might not know or understand that they can have an opinion and stick up for themselves.
Yeah, people have tried switching up our agreements on the spot. At the time, I was naive and let it slide because I thought I was getting paid. But I never got paid, like I was supposed to, so I got outta there pretty quickly. There are some extremely sleazy, lying, manipulative people out there. Nothing can really prepare you for that except experience with it. You can be warned ahead of time about people like that, people can tell you about all the shady characters out there and how to watch out for them, but once you're in that situation, it can be difficult to get out of.
That might also be a big reason why so many directors, producers, and companies like to hire new girls. Not just because audiences want fresh faces, but because new girls are.... well, like I stated above, new girls aren't completely aware of how the industry works. So they're more willing to do certain things because they don't want to limit themselves- they want the work because they want the money, and if a director says, "Oh, if you just let this guy fuck you from behind while you give this other guy a blowjob, you'll get $300 more." So the girls are like, "Alright, yeah, not a problem."- while on the inside, in her mind, she's thinking.. "I don't really want to do that. Oh well, I'll just say yes and get it over with." That might not be the best example, but I'm sure you get what I'm saying.
After a girl has so much experience in the adult business, she develops a sense of right and wrong, shady and genuine, lying and honesty. She's been around the block, she knows what she wants, and she's not afraid to stand up for herself and isn't as vulnerable to bullshit artists.
Now, not every guy hiring girls in this business is shady and manipulative. I think there are way more decent, honest, hard working, professional people out there in the adult industry than there are shitty people. But those few shitty people tend to give the whole industry a bad rep. You have to be willing to look past the bullshit and see all the good out there.