If they came and spoke to me or called me or told me who left the note then I would talk to them. but the city noise ordinance is 10pm and they can deal with that. It's not your fault they get up at the buttcrack of dawn. Get a sound machine... use ear plugs... I mean you are obviously using eye masks already because if you are sleeping at 8pm then it is still light out side in many places this time of year.

Anyone who leaves notes like this better actually have a REAL issue or put their name with the request so that a discussion can be had. We had a real problem. Our neighbors were coming home between 11-12:30 every night in the summer and would lock their car 3 or 4 times. It woke us up every night because their car parks right under our window. I went over there one night and asked them to knock it off. It happened maybe one time in the past 2 years since talking to them about it. When you have a discussion with your neighbors and explain why something is a problem then you can make change. Anonymously telling your neighbors that they are too loud at an hour when more kids are still awake is ridiculous and childish.

If I were, I would do nothing until they actually talk to you.