DovidH, if a heart surgeon says that because the patient didn’t ask me not to operate while drunk, he implied permission, does that work?
There are two primary options as far as parents and MBP: either they believe in it and want it, or they don’t and they don’t. There are few people that would say: “Well I don’t think MBP is important but I sure love Herpes.”
Now the question is back to how anyone can justify doing something dangerous to someone else’s infant without the parents knowledge.