It's really hard to believe however screenshot is not enough.
I've gotten plenty of PMs from members I've negged asking me how much it would take for me to remove feedback, so I know other members have probably gotten similar offers. While it might be tempting to some, it's a stupid-ass thing to do 1) morally, and 2) because you get things like this thread, where apparently after the request was made the other member blows the whistle. Ethics aside, if you care one whit about your reputation on this forum you'd be crazy to try to extort someone via PM.
I'd be interested to hear what vlom has to say. Has anyone PM'ed him about this?