[Scanu]

I understand your worries but please can you tell the reason you don't like the idea?
As BirdOPrey5 said if a hacker finds a way to access admincp of vbulletin, then he could do anything he wants using plugins: editing, removing and adding files, access database etc..
This modification is secure as the admincp is and if the admincp isn't secure for you then this mod won't make it less secure. If a hacker is able to enter to your admincp then i'm mostly sure he knows how to edit files using php. This mod won't make any difference actually