That would be kind of pointless, to me. O_o
Either way, I, personally, think GMs should have legits on the server they GM. Not only does it give them a chance to experience things as a player, including possible bugs, glitches, and even things that are overpowered, but it gives them a time to relax when the friends that they have on that server.
That's my own opinion~ Anyways, back with being ontopic. XD Impersonation, at any time, will be hard to prevent, like I already said, systems or no systems.