I think this would be a pretty terrible abuse of that law - it would also be quite non-standard since listening to music on a boombox hasn't been prosecuted AFAIK[1].
Oh as I mentioned in a different comment I think this should be illegal and might already be illegal - but pulling some rando law out of the aether to force the charge isn't a great tactic.
Edit: Just to clarify, one of the other reasons I'm skeptical of using copyright law for this is because the intent doesn't match what the officer's intent would be allowing for officers to have a pretty good chance of avoiding any repercussions and because the penalties of sentencing are inappropriate. There are existing legal recourses in most instances for restricting the ability for civilians to record police incidents - if an officer is abusing copyright law to accomplish this silencing then they are likely running afoul of those laws and should be sentenced with breaking those laws since the penalties are more appropriate.
1. I'm going to guess it has happened sometime because racism, but it really shouldn't be. And thankfully a quick googling didn't turn up a litany of results.
Oh as I mentioned in a different comment I think this should be illegal and might already be illegal - but pulling some rando law out of the aether to force the charge isn't a great tactic.
Edit: Just to clarify, one of the other reasons I'm skeptical of using copyright law for this is because the intent doesn't match what the officer's intent would be allowing for officers to have a pretty good chance of avoiding any repercussions and because the penalties of sentencing are inappropriate. There are existing legal recourses in most instances for restricting the ability for civilians to record police incidents - if an officer is abusing copyright law to accomplish this silencing then they are likely running afoul of those laws and should be sentenced with breaking those laws since the penalties are more appropriate.
1. I'm going to guess it has happened sometime because racism, but it really shouldn't be. And thankfully a quick googling didn't turn up a litany of results.