I approach it in the same manner as a referee making a bad call. You get on their case, hopefully influencing the next call(s) to go 'your way'. Of course, this assumes the ref isn't technically 'cheating', but works on human nature.
When I'm in a match and see strange stuff starting to happen, if I feel it may influence the outcome I'll take action, verbally asking the old "are you sure'...but then pressing for a mark. Second time it's a nice loud, "come on!" Throw in a stare down, and finally a "what are you effing kidding me" and all but the most hard core cheater will back down. And since compared to my, um, 'other sport' buddies, tennis guys are wuss city, they usually back down.
Except the lawyers, they're sometimes out to play head games as that what's they enjoy about tennis. I just played one of those this week. Had an unusual experience too. The dude, a strange one that I am newly playing, hits a little floater, short, that he chooses to come in behind for some reason. I approach, racquet back for a smash, and he hits the dirt, fetal position, I mean ON THE FLOOR, covering up.
I tap it off to the side and walk back to my baseline.
Earlier in the match he made a call which he persisted in hotly disputing. I had come in and hit a winner, hitting the ball cleanly on my side of the net. My racquet carried over the net after contact, not touching it. He calls, from well behind HIS baseline, 'you went over the net...my point!' Then asks, "did you touch the net?"
I replied, "I didn't make a call, did I?" Then explained that I did not touch the net, nor hit the ball while on his side of the net. And that it was my call to make in any case and I made the correct call, a non call. He then went on, "but you admitted your racquet went over the net" to which I said, "sure, doesn't mean a thing".
To make a long story short, guy wouldn't accept that I had:
a) Recently read in Tennis mag about this very call.
b) Know the rule.
c) Up on rules that while he can question my call, it is my call, and swinging beyond the plane of the net without contact is not an infraction.
The guy is a bankruptcy lawyer and stuck to his 'guns'...has "the rules" "printed out at home and studied them" and all that. Finally, without us coming to an agreement, stands up and serves without another word.
A cheater? No, I did not think so in this guy's case. Just another twerp that has made the athletic choice between bowling and tennis and chose the latter...
Sakki