story
But that's not (just) what the officer was doing - he was playing music as background to his business operation, which RIAA have definitely sued establishments over[0]. If you're playing music as a soundtrack for your business (in this case, the business of law enforcement), you need a license. Even in a non-business context, if they had a chance to sue you for playing music in public, they would. There just haven't been any prominent/worthwhile cases for them to do so. Just because it hasn't happened doesn't mean that isn't what the law allows.
[0]: https://www.frantzward.com/news-blog/june-2017/let-the-music...