[Rich]

Originally Posted by JugglingReferee

I'm guessing that the illegal defense occurs when playing defense in A's back court. Slapping the ball away sure sounds like defense to me. Even if B doesn't obtain possession, team A now has less time to avoid a 10-second violation. Blow the whistle, voice the defensive violation, and assess the penalty. If you don't yet have a penalty for this, you can consider to use what we use in my province: Team A gets a front court throw-in at the foul line extended.

If you don't allow back court defense, it sounds to me that A basically gets a free pass to get the ball to their front court (save a traveling or 10-second violation, etc). Even if there is still no in-bounds possession by A, B still cannot intervene. So call the violation.

The play in question happened at under 2 minutes -- in the OP it was communicated that this was legal at that time and it was, in fact, an IW.