I originally got an Amazon Tap instead of an Echo because it required hitting a button to listen. Then they added an all setting that let me toggle the always

I originally got an Amazon Tap instead of an Echo because it required hitting a button to listen. Then they added an all setting that let me toggle the always on capability and I realized it was just a software button and that in theory it could listen in whenever and I'd never know. The lack of reliable user controlled methods of limiting recording devices is disappointing. Is there some sort of sound dampening material that could be made into a cover for devices like this?