I think rewarding kids for high achievement or excellent behavior is great. But I guess you must be careful not to intrude and take away from what other teachers are doing. Communication and not assuming things are your keys sometimes. I was probably remiss at this at times but if it was just between me and the P I found it easier to say Im sorry than risk being turned down sometimes. I picked my battles. I was very fortunate in 40 yrs of never having a principal on a power trip. I didn't always get my way but framing it as being for the benefit of children usually did the trick. And it WAS for the children. I worked in a very small elem. school so things were much more flexible. My advice is BUILD relationships with colleagues and keep the boss in the loop at all times. The more positive you can make something the more likely it flies.