You don't think a locked room with one entrance/exit is a safe place to leave a pre-teen? No one is talking about toddlers for god's sake. What if the child in the original post was 16? You want a strange man walking into a room with your 16 year old daughter? A room where the door was locked and she had expectation of privacy and is maybe napping in her tshirt or taking a shower?
Do you have eyes on your child all day every day? Are they never alone? Jeez, when I was 12 I babysat my little sister all day every day in the summer time. I would venture any normal 12 year old is perfectly capable of being by themselves for 15 minutes. I bet they could even handle *gasp* a whole hour!
If Disney makes you agree to such a policy then yes, if you stay there you've chosen to deal with it. My understanding is they AREN'T having people agree to it or even warning them until it happens the first time. There certainly isn't anything on the website about it that I have seen. So what about someone who isn't on DIS Boards? They pay thousands of dollars in advance for a vacation only to get there and either be told this policy at the desk or find out about it the first time someone barges in their room. At that point are they supposed to "go somewhere else if they don't like it"?
My personal problem with it is that nothing about it is secure. Those CMs entering rooms are technically under housekeeping. Have they had background checks? Security clearance? How do I know THEY aren't the traffickers everyone is worried about? Does Disney know? They have taken a knee jerk reaction to an extreme. They are grossly violating the privacy and safety of their customers and gaining nothing from it. If I was a decent criminal, looking in my room for 2 mins is not gonna catch me by the way. (p.s. I worked in law enforcement for many years, I'm not coming at this from an uneducated point of view.)
And yeah, talking on these boards is not going to change the policy. But this is a place for discussion after all.