From IAABO Dec. 2011 Newsletter:

[bob jenkins]

Originally Posted by HawkeyeCubP

APG - It's the same reason the NCAA-M (@ Michigan State?) play you posted video of earlier this season was discussed and ruled an IW instead of the backcourt violation that was originally whistled by the trail.

It's the difference between Player Control, Player Control Inbounds and Team Control.

It's also the difference between BC violations and TC fouls (and the requirements for each).

edit: or what APG said.