If a girl screens well, and uses hobby boards, she should be able to avoid jerks of any color. If all she knows is posting on backpage and hoping for decent clients
well, anything she can do to feel safer, go ahead.
I used to take any girl with a "no AA rule" off of my list to see. I made the assumption they were racist and I didn't want to support them,. After reading more about why, and seeing it even from black girls, I no longer think so.
Can you imagine how many pimps or wanna be pimps patrol backpage looking to add to their stable. I hate to assume every pimp is black buuuut... every arrest I see makes it hard not to.
As far as size being an issue... while I can't hold a candle to the average pron guy, I've got a little more than most. Enough so that it's uncomfortable for some women. I've even seen a few that request "no magnum size guys" on their website. So I don't bother. I try to feel out the lady after screening but before the appointment, to make sure she's cool with it. I have found a few times where my references had clued her in and she was looking forward to it. It's about 50/50 with providers as to whether it brings anticipation
or dread.