Tripping, Or Being Tripped ???

[BryanV21]

Originally Posted by just another ref

Obtaining a spot legally and having legal guarding position are not the same thing. It is not illegal to fall down, unless you fall into the path of another player. If that other player come along and trips on you after, it's his own fault.

There's a way to determine what B1 did wrong, and therefore call a foul call. There is nothing to say what A1 did wrong to be at fault and called for a violation. If the players were standing, would you call it differently? And if so... Should you?