I presented a play in another thread a few months ago that is somewhat similar to this situation. I was told repeatedly that you had to have intent on a discarded bat to call interference. Is that only for interference on a fielder attempting to field a ball or interference on a throw?
I think the confusion can be found in the title of this thread. "Batters Interference." This is not batters interference in any way. If it's interference at all, it's runners interference.
For batters interference you have to have the batter committ an overt act while in the batters box. Runners interference is a different story, but on a discarded bat, I'm still not so sure intent isn't required.
Here's the thread with the play I mentioned.
http://www.officialforum.com/thread/21693
Tim.