Ok i read all the thread. I just want to point out. Im not in the favour that someone reads my 'private messages' but if someone is bothering someone then he or she can report it to the mods and then they can sort it out. And maybe one or two head admins have the power to look through PMs.
No, only excessive InterGender PMs are monitored. There have been quite some instances in the past, and continue still, that prompt us to do a check every now and then.