Ok, a few points of clarification seem to be needed here. And I, in no way, hold anything against any of you who disagree with my side of it. You all make valid points on your side of it. However, some other points need to be made clear.
1) The parents almost always turn a blind eye to what the kid does unless it's being done to them. I've witnessed this time and time again. It even got to the point where I'd say "are you going to let him keep that up?" to which I'd get the reply "no, he's gonna go for a nap soon if he doesn't stop". And that was it. The kid continued what he was doing and the parents blocked it out.
2) This kid has more toys than a little bit, including 2 other hockey sticks. Now I'm not saying it's ok to break one because he has back-ups, but the stick getting broken is really not depriving him of anything. Plus, the shock of it getting broken seemed to have driven home the point that he was doing wrong as he did not go for another stick, which was lying nearby, and continue what he was doing.
3) The kid is like a nephew to me. I love him dearly, as he does me. He is not, and never has been, afraid of me or my brother. And after the little incident I mentioned, he seems to have a measure of respect for me, or as much as a 3 year old can have anyway. Or he at least learned where the boundary lies with me and doesn't push it. He'll push his parents endlessly and anyone else for that matter, but not me.
I didn't intend for this to become a "abuse vs. discipline" argument because everyone has their own belief on the matter and it's very seldom anyone on either side will bend on the issue, myself included. I just wanted to know who was more in the right on the matter of the OP.
Thank you all for your responses on the subject.