Mixed bag. Some people come to me for coaching because they love SS: they've read the books, watched the videos, listened to the podcasts, etc etc etc and they are just all about that life and want to be sure they're doing it right.
More common is they've skimmed it, seemed above their heads but well thought out, so sought professional help to do it right. Maybe read some SS articles here or T-Nation/PJ/HuffPo/wherever, maybe watched some youtube stuff, maybe not.
Some don't really care and haven't read it at all. They just want me to tell them what to do and they'll do it.
At this point anyone who comes to me, comes specifically for strength and barbell coaching, usually specifically SS. Even if they haven't actually read SS, they want to get stronger and already see me as someone they can trust to get them that way. So no, I don't lose people because they aren't "entertrained" enough. But as a generic personal trainer, that might be an issue.
Don't know what others' experiences are but that's mine.