Well, yes, I guess there'll always be clients like that. I've generally been quite fortunate that I've been able to be fairly selective in life about who I work with/for, and I've rejected as many clients (more in fact) than have rejected me.

Saying that though, in those kinds of situations I do usually try and have a conversation with them about why they want to make those calls - they're paying me (or wishing to) for my professional expertise, and part of that is about educating people around surface choices which seem like a bargain but come with potential hidden costs and disasters. Some can't be helped of course :)