I tend to agree with Sam and Dan. The purpose of the rule, as I understand it, is to prevent the offense from attracting, creating, or tempting the defense into making a play so that the offense can possibly advance a runner after the play is basically over (pitcher has the ball in the circle and would be preparing to deliver the next pitch if it weren't for the antics of the offense).
Runner returning to 3rd and then stops to do a little stare down with the pitcher... anything more than a very slight hesitation should be rewarded with an out. JMHO
The ASA POE #33 statement about approaching 1st "If a runner is moving toward a base, other than 1B," I assume means the intial approach of the BR and not the runner who has already passed 1st base and is now returning??? Anyone wish to clarify?
e.g. R1 & R3, pop up fly to pitcher, R1 steps a few steps off of 1st and stops to watch the catch, pitcher catches the ball in the circle, pitcher turns to look at off base R1, R1 while staring down with the pitcher begins movement toward 1st and then stops a couple steps short of the base. I feel R1 is tempting the pitcher to make a play (purportedly so R3 could score). Unless the pitcher makes some form of a play, I think the proper call is - R1 is out. R1 only began motion after the ball was in the possession of the pitcher in the circle and only stopped once after beginning that motion. I don't think that POE #33 should save this runner from enforcement of the Look-Back Rule just because they are headed BACK to 1st base... and I believe the LBR is appropriate for this type of situation.