This seems to be a social problem masquerading as a technological one: recording devices that transmit what they hear are a dual-use technology. Just as an abus

This seems to be a social problem masquerading as a technological one: recording devices that transmit what they hear are a dual-use technology. Just as an abuser might use such a bug to prevent their partner from seeking help, so might an activist attempting to document police abuse of power. In the former situation, we can agree that the victim should have the ability to force all listening devices off, whether or not they know the device is there. In the latter, the police should not have the option to unilaterally disable surveillance. We can't solve a social problem (is this an ethical use of covert surveillance devices) with a technical solution. We've tried it in the past, and it hasn't worked. Neither can we really solve this one with laws: abusers, no matter who they are, will do whatever they think they can get away with, and preventing victims from gathering or sharing evidence lets them get away with a lot more.