Restraining line? I'll assume that this is some sort of "plane indicator" due to a really tight OOB space limitation.
Annnnnnnnyyywhoooo...I can think of a few responses to consider so here they are:
- If this is one of those lazy inbounds after a made basket and everyone else is already running back up court I would be more inclined to not have called a violation and tell A1/A2 to be sure they know where the line is next time...keep the game moving.
- If this is due to some sort of confusion due to the way the lines are painted early in the game, I would stop them, show them the line boundaries and make them inbound the ball properly.
- If Team B is pressing I would whistle the violation.