it's better to be against company SOP, than be deaf
Actually, hearing damage is not really the main hazard here. The biggest risk is infection, and specifically viral types, such as Herpes Simplex, which causes "cold sores" on lips etc.
Earpieces may be cleaned by some of the wipes which companies generously provide - the results of such wiping would be bacteriologically dubious, to say the very least !
But, can you imagine trying to wipe the surface of a mike ? And we all know that to get good transmission the mike needs to be near to (maybe touching) the lips. So, if the guy who did the leg before yours has Herpes Simplex . . . . . . . . need I say more ?
In such a case, if a compensation claim was made against an airline, it's difficult to see any kind of defence at all that could be put forward.