> Unless you think it violates copyright to play music in public spaces.
Generally, yes:
https://www.law.cornell.edu/uscode/text/17/106
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17 U.S. Code § 106 - Exclusive rights in copyrighted works
Subject to sections 107 through 122, the owner of copyright under this title has the exclusive rights to do and to authorize any of the following:
(1) to reproduce the copyrighted work in copies or phonorecords;
(2) to prepare derivative works based upon the copyrighted work;
(3) to distribute copies or phonorecords of the copyrighted work to the public by sale or other transfer of ownership, or by rental, lease, or lending;
(4) in the case of literary, musical, dramatic, and choreographic works, pantomimes, and motion pictures and other audiovisual works, to perform the copyrighted work publicly;
(5) in the case of literary, musical, dramatic, and choreographic works, pantomimes, and pictorial, graphic, or sculptural works, including the individual images of a motion picture or other audiovisual work, to display the copyrighted work publicly; and
(6) in the case of sound recordings, to perform the copyrighted work publicly by means of a digital audio transmission.
---end quote---
There are some exceptions to this regarding specific permitted performances at 17 USC § 110 as well as the general exception to copyright in fair use at 17 USC § 107, but I don’t see an obvious argument that these or any other copyright exceptions apply to this use for this purpose. (I can see an argument that the police use would render the recording and reuse by the person recording the officer fair use, but that's not an issue here, because we already know that copyright protection schemes by platforms are hostile to fair use.)