Ok. That makes sense and it was along the lines of what I was thinking. A few follow ups though. Are there any guidelines for investigating noise? The noise level was admitted by one of them as not having broken any regulations, but they it was loud enough that they thought it could disturb the neighbors.

As far as investigating minors drinking, so can they just go up to any house and ask for the the ids of everyone who is drinking inside the premises? If they weren't investigating the noise, then surely one male with a beer in his hand who is 21 isn't enough to search everyone inside the house... but I could be wrong.

The Police officer merely said the door had to stay open so she could see inside. I also understand their need to be careful and mindful of their surroundings, how are they to know if they cannot see? Various things I have looked at have mentioned stepping outside (shutting the door behind you) and talking to police. None of them are citing any laws, but it doesn't sit right with me unless they have a reason for suspecting trouble from within.

I just want to make it clear that I am not trying to find out where these officers messed up and go screaming about misuse of power. In that situation, I was so confused about what they could and couldn't do under law. I am merely attempting to understand.