The fact that parents don't know and don't understand what their kids are doing on Myspace and Messenger means that they are slighttly paranoid about the potential consequences of what they get up to.
I'm sure putting a little 'call the police' button in the side of the messenger window will help catch a couple of 'groomers' but I'm not sure it's a healthy thing for Microsoft to have done. The problem is that little kids are, generally, little bastards. Hitting the fire alarm in school might now be replaced with accusing random strangers with grooming.
If there are high numbers of false positives, it could backfire for Microsoft as the perception grows that it is dangerous to let children use messenger.
Didn't anyone teach these kids not to talk to strangers?