Why are so many cops blasting music while being filmed?

This is why stealth recording is the best way - don't put the phone/camera/recorder in their face. Pretend it's a conversation not being recorded in any way (but actually is).

Police are putting their guard up because the recording is in their face. This is human psych 101. Don't play into the situation to cause the escalation in the first place.

Is it ethical or moral what they are doing? Absolutely NOT.

But it's more important to remember the long term goal.

Intimidating the officer is a bad idea and not how you make this work. Honey vs. Vinegar.

You want them to be at ease and if they are doing wrong, you want them to pull the noose themselves. They always have the option to "do the right thing". If they choose not to, that IS on them but better to be non-confrontational about how the situation plays out.

There are audio and video recorders that can be pretty stealthy (I own several). Don't just pull your phone out and push it into their faces. Plan for it. Wear a stealth recording device.

Think "Dash Cam" - it's always running when you drive because that way you and others don't get distracted by it. Same here.

I hope live streaming services at least let the live videos keep on streaming even if it doesn't get shown to the public and that the streams are saved. It'd be a matter of public safety if the streams cut off.

I also think this type of action by the police should be illegal.