Was it an accident or negligence?

Was it an accident or negiligence?  That's the question my husband asked me after I told him that one of our children had broken the television.  I didn't want to tell him it was our son.  He has a tendency to break things and has gotten in a lot of trouble lately.  Of course he knew who did it, but I tried.  My son was playing around with one of those rubber exercise bands and when he twirled it, the handle hit the TV.  While nothing actually broke, apparently he hit some pixels or something and there is literally a web pattern on the screen that looks like broken glass. 

So, was it an accident or negligence?  My son did not mean to break the TV and he wasn't trying to hit the TV, so yes it was an accident.  However, where was I?  Shouldn't I have kept the whole thing from happening?  I was in the other room trying to get some exercise.  First of all, he should not have had the exercise band and second of all, I should have been watching him.  So there was definitely negligence on my side.

The next question is, what should the punishment be?  While it was an accident, he has been told not to play around the TV especially when he's throwing something around.  But he is only three.  Obviously he's not allowed to watch TV and that may be the case for quite a while because we can't afford to replace it right now.  Then I come back to how much of it was actually my fault.  I know I can't be around all the time and I can't stop everything, but isn't it just as much my fault as his?  The crazy thing is that I'm not really that mad at him.  It was an accident and I feel I'm as much to blame as him.  I should not be allowed to watch TV either.  Oh wait.... I can't.