To throw in a new aspect:
This shutdown-feature also works remotely which means that (at least theoretically) anybody can shutdown your PC without any special tool. All he has to do is to know your IP and Password (worse if you even don't have one). But although you have a PW it's not quite difficult to find out. -- okay, I guess this info is not new
Tried this with some friends
and worked perfectly in 99% ...