My ultimate decision is that... You call it when you see it. If it is at the lower levels (5 & 6th grade) you give a quick explanation of what the violation is, especially if the player gives you that "RCA dog look". Call it as often as you see it or leave it alone for the entire game.
I used to think that giving a verbal warning once at each end was the answer, but soon realized that my warning was only heard by a few players and I refused to continue this practice throughout the game. However, by doing this, I was creating a disadvantage to future (currently bench-bound) players because they probably had not heard me. Additionally, I was venturing into the area of coaching. YIKES!
