True friends would not do that. I believe they are people looking for a place to party. If you are renting, these people will get you evicted. If not a visit by your local law enforcement with fines to match.
We have all been there. Like to party. But there is a time and place for everything.
Simply put, if you can't be there to keep it to a dull roar, they need to go someplace else. No disrespect implied here. Just offering advice.
A device added to a stereo to warn of impending power shutdown can be easily bypassed. Then the party continues. Imho