I think camming is all about what you are comfortable with. Yes, this is a job, and yes we are being paid, but it's still our bodies we are playing with! Health is of the utmost important and any worthwhile customer is going to realize that and not be upset if you can't go harder/deeper because it hurts you!
If I'm really sore, I do take the next day off... Or I just don't do shows and focus on doing fun stuff in public. In general, I try not to wear myself out too much to the point of being sore, but it does happen. (I did have 11 orgasms in one day last week! :eek)
As for faking, I realize a lot of girls do it, but it's totally not my bag. Lol. I love masturbating and cumming... Why fake an orgasm when I can have a real one!? Plus, I'm all about being real anyways. If I'm going to fake, I would tell the guy I was going to fake. I've actually had a few say that was fine, lol. (For example, we're in a private and he wants me to cum before his tokens are up, I say I probably can't, but I could fake it if he likes.) It's not like I'm not still enjoying myself. I used to fake when I first started, but that was because I didn't really know how to get myself off with toys... And then I learned! Camming has been a great way for me to find out multiple ways to please myself, lol.
I suppose it depends on the environment... If I was constantly in shows I might start faking. I do make quite a bit from groups and privates... On my really good days, I've often had a lot of privates - 60 tokens a minute (plus spies) just can't be beat! Lol. But I make a lot from groups or tips as well. Either way, it is a lot harder to get shows on MFC, but the public aspect totally makes up for that, I think. But some girls just aren't into that style.
Btw, I totally agree that what you said, LovelyLemon, was very well put. Good job! =)