[just another ref]

Two things: One is a fact. One is my opinion.

Fact: (already stated) Not all fouls have anything to do with LGP. B1 is standing in the lane, stationary, with his back to A1, on one foot even. Clearly he does not have, and has never had, LGP. A1 drives to the basket and dunks on B1, knocking him to the floor in the process. Foul on B1?

NO

My opinion: Leaving the court for an unauthorized reason is not about players who happen to touch the line with one foot when space is not an issue. It is about a player deliberately going out of bounds to reach a spot that he would have otherwise been unable to reach in a timely fashion had he not done so. I don't see myself EVER calling this violation for a player touching the line with one foot, let alone for a player standing still in a wide open space touching the line. This would be right up there with calling 3 seconds on a player stationed in the high post, not involved in the offense, who happens to touch the free throw line with his heel.