You are absolutely correct, John.
I tried rolling my cues on different tables, and they DID roll significantly different on different tables.
I also trust my eye more when judging whether a cue is straight or not. But it is not a popular way to show others because some can see the slight warp, many cannot.
My friend has another way of testing the warp. He holds the cue at balance point with both hands, straight up, then spin it into the air. just for 1-2 second glance to see whether the spinning cue moves or not. if the cue spins perfectly without noticeable fluctuation, it is straight. This method works well, but, again, it is for one's self only.
I agree that spinning the cue on a lathe is the best possible way to decide.
and yes, wood can move, but no one can say for sure if it will move to straighten up or warp worse.