[jariel]

This argument would be completely unnecessary.

Playing music to yourself, your friends etc. is 100% legal in all cases.

The cop doesn't need to make any arguments whatsoever about who it's being played for.

The person doing the filming and distributing is the person infringing.

It's completely obvious, there is no ambiguity.

The only approach, however hairbrained and ridiculous - would be for the IP owner to go after both the content video/distributor - and then somehow also rope the cop in as though they were somehow 'part of the preformative act' of making the video. But that's beyond a stretch.

In reality there are no hairs to split. If there is infringement, it's the person making the video.