[BillyMac]

Thirty seconds left? Delay of game warning (or technical foul if previously warned for any delay of game).

That's what I would do, however 9.2.10 SITUATION A (below) suggests an alternative harsher penalty.

9.2.10 SITUATION A: A1 is out of bounds for a throw-in. B1 reaches through the boundary plane and knocks the ball out of A1’s hands. Team B has not been warned previously for a throw-in plane infraction. RULING: B1 is charged with a technical foul and it also results in the official having a team warning recorded and reported to the head coach. COMMENT: In situations with the clock running and five or less seconds left in the game, a throw-in plane violation or interfering with the ball following a goal should be ignored if its only purpose is to stop the clock. However, if the tactic in any way interferes with the thrower’s efforts to make a throw-in, a technical foul for delay shall be called even though no previous warning had been issued. In this situation, if the official stopped the clock and issued a team warning, it would allow the team to benefit from the tactic. (4-47-1; 10-1-5b, c; 10-3-10)

B1 reaching through the boundary plane and knocking the ball out of A1’s hands would always be a technical foul, regardless of the score, and time remaining.

Is that the same as B1 simply holding the ball?

I look forward to further discussion of 9.2.10 SITUATION A and hope to learn something.

One thing I'm sure of, no rule basis not to allow eligible substitutes (dead ball, clock stopped), so let them in.

Five seconds left? Let the clock run.

That's what I would do, however 10.4.10 SITUATION A and 10.4.10 SITUATION B suggests not to ignore certain delaying acts (knocks the ball out of A1’s hands, crosses the boundary line and fouls A1, reaches through the out-of-bounds plane and touches the ball while in the hands of A1), even if there's less than five seconds left, but these would always be a foul, regardless of the score, and time remaining.

Is that the same as B1 simply holding the ball? I don't believe so.

10.4.10 SITUATION A: After a field goal, A1 has the ball out of bounds for a throw-in. Thrower A1 holds the ball: (a) B2 crosses the boundary line and fouls A1; or (b) B2 reaches through the out-of-bounds plane and touches the ball while in the hands of A1. RULING: It is an intentional personal foul in (a), and a technical foul in (b). In (a), such a contact foul with the thrower during a throw-in shall be considered intentional, or if it is violent, it should be ruled flagrant. COMMENT: Either act is a foul and it should be ruled as such whenever it occurs during a game without regard to time or score or whether the team had or had not been warned for a delay-of-game situation. If the player making the throw-in (A1) reaches through the out-of-bounds plane into the court and B1 then slaps the ball from the hand of A1, no violation has occurred. B1 has merely slapped a live ball from the hands of A1. (4-19-3, 4; 9-2-10 Penalty 3, 4)

10.4.10 SITUATION B: After a field goal, the score is A-55, B-54. A1 has the ball out of bounds for a throw-in with two seconds remaining in the game. A1 throws the ball toward A2 who also is out of bounds along the end line. B2 reaches across the end line and grabs or slaps the ball while it is in flight. Time expires close to the moment the official indicates the infraction. RULING: A technical foul is charged against B2. The remaining time or whether Team B had been previously warned for a delay-of-game situation is not a factor. No free throws are awarded as the winner of the game has been determined. (9-2-10 Penalty 3, 4)