Partying tentants and timid board

When a complaint is made to the board by an owner regarding tenants, (younger people partying - ok within normal standards) that leads to yelling in the halls & stairs and using profanity  on their deck until 5 AM, who is responsible for handling the situation?

I say an owner doesn't want to make an enemy, and the board member should make a courteous call explaing the rules in condo living.

The board wants only to mention in a letter to the owner which takes time. The board also thinks that this type of thing happening only twice is not enough to complain about.

A quick nice call would nip it in the bud, in my opinion, but the board is wondering about whose responsibility this is for the past 6 days!

We have few tenants in our complex, so it is not a problem that we are accustomed to.