I can't speak to the actual legality, but I strongly feel that a less-dysfunctional system would account for the intent of the officer. It is undeniably an attempt to suppress widespread dissemination of video documentation of their actions, by taking advantage of a known flaw in the technology most commonly used to do so. At the very least, this should be a fireable offence on the first infraction, akin to tampering with their body camera.