This really comes down to how the owner of a machine wants his machine treated. Some people want their machines taken care of, some don't mind rough shakes and nudges.
It's like when you go to someone's house and they want you to take off your shoes before stepping on the carpet. Ok, it's their house. Do you argue that carpet can handle shoes and can be cleaned?
Problem is when we walk up to a machine we don't know how that particular owner feels about this argument so it's best to play it safe and not overdue it.