The whole point of this thread is that Apple is telling us to not rely on dead simple devices (camera covers, tape, etc.), and instead to trust their internal mechanism that they claim can't be beat. If people take them at face value, but the mechanism is in fact complex enough to admit an exploitable vulnerability, that's a net loss of security, and is a step in the wrong direction.
But you are talking about microphones which you cannot simply cover.
I admit, muffling them is better than nothing – but in the case of microphones Apple doesn’t even advise you not to cover them.
Either way, this is just an effect of common covers seemingly breaking screens. Which sucks. However, depending on your risk profile the re-assurance of a hardware solution that lights up the LED might be plenty for you.
