[greymule]

The reason I'm asking is that I used to give a signal (probably because I saw MLB umpires do it) but then stopped when other umps, some on this board, argued that the signal was superfluous and, a few said, worthy of a "Smitty").

I can't say I've ever had a problem in an actual game either giving the signal or not giving it. As for foul tips on checked swings, I think I reflexively signal when that occurs. In other words, as Tim C says, I give the signal when it's advantageous to me.