The way I thought/think it's SUPPOSED to work is - if "normal" access (cleaning the room if it''s supposed to have maid service, etc.) does not occur as "normal" (guest leaves for parks, CM enters on whatever the room service schedule is (I realize DVC is different), or is denied on numerous/constant instances, or there is some other reason for "due alarm" (kind of like probable cause), THEN they would utilize the "come to the door, KNOCK", then enter (maybe a "triage type" discussion would take place first to determine necessity, or if there is reasonable explanation if given), and/or maybe some sort of management position CM would be consulted first, prior to entry. I would think there HAS to be some kind of SOP regarding this whole thing. The whole "we can enter at any time" written on the DND tag is a sort of CYA, NOT what's is GOING TO HAPPEN IN EACH AND EVERY CASE.
Given that sort of general scenario (I've laid it out briefly, after quickiy thinking about it, so please - no flames if I've missed something) I personally have absolutely NO problem with it. I'd rather be safe than sorry, and can only assume that - barring something exceptional happening (accidents, and things DO happen - in ALL things, ALL the time, but they are the EXCEPTION, not the RULE) good judgement and etiquette would be used.
I"ll admit I've not read the other comments/forums about this, but could it be a question of "the internet losing its collective minds" as Pete always says? Blowing things WAAAAAY out of proportion?