If you don't assume the internal wiring is as described I do not think there is a way for you to guarantee the microphone is not recording. It's even less obvious than a camera lens being covered or not, and taping over the "microphone hole" won't actually block receiving sound at all.
I do physically disconnect or cover cameras. My desktop computer has no microphone unless I plug one in. Laptop and phone though? I definitely remember in the aughts that the police could remotely turn your phone into a bug without any user indication at all. To the best of my knowledge the only way to actually be sure you aren't being recorded with your own equipment is to remove power... of course now the batteries are soldered on, totally a coincidence I'm sure.
I do physically disconnect or cover cameras. My desktop computer has no microphone unless I plug one in. Laptop and phone though? I definitely remember in the aughts that the police could remotely turn your phone into a bug without any user indication at all. To the best of my knowledge the only way to actually be sure you aren't being recorded with your own equipment is to remove power... of course now the batteries are soldered on, totally a coincidence I'm sure.