RPD,
You got right calling it "the dance". I have never understood the incredible preoccupation with runners on base. Most AAU and HS coaches go so overboard on this part of the game.
How many times do you see a runner actually get picked off of second versus the number of times the play goes awry or a base hit occurs because the SS or 2B is out of position?
This situation also tends to seriously mess up young pitchers. They focus too much on the runner, to the point for many of them that will try to come to the plate while still looking at the runner. For most young pitchers, this usually results in fewer strikes thrown. They get behind in counts and either groove pitches or walk batters. Consequently the exact situation you are trying to avoid (he advancement of the runner) gets compounded.
At the HS level, I feel having the pitcher "freeze" the runner, stepping off, and the occasional quiet (no glove slap) pick off play are far more effective than having your middle infield running back and forth.
I want the pitcher more focused on the batter than the runner. Once he has decided to throw a pitch, I want his head and eyes on the target to give the greatest possiblity of throwing a good pitch.