Police blare copyrighted music to prevent videos being posted to YouTube

Possibly treat this as a public performance?

From https://www.bmi.com/faq/category/copyright

A “public performance” of music is defined in U.S. copyright law to include any music played outside a normal circle of friends and family that occurs in any public place.

You should get some copyright holder to sue them for it. You’d think some band would want to join the cause and if it is an aggravated case they could get fined $150,000.