ran into a foot faulter in a league match about a year ago. he started behind the line, then stepped over it a good foot during his motion. I thought about calling him on it but it was such an easy win for me I didn't bother. ( I won the last set 6-0 )
if it was a close match, I would just call it on him as soon as I first saw it, he might get mad but if he is clearly foot faulting what can he say? cmon , its cheating. clear and simple. foot faulting repeatedly is just as much cheating as calling balls out that were clearly in.
you gotta say something!