A bit of a tangent, but as a freelancer who picks and chooses who to work with, have you ever been hit with a discrimination claim, e.g. you turn down a job, and next thing you know they are claiming you won't work with them because they are black, or gay, or whatever.

How much do you need to document the reasons for turning away a client? Or is there some kind of "at will" protection that applies to freelancers?