Well, it makes the situation clear. Player getting a temp sub for him would usually leave contact info to the person taking over, just in case someone wants to do some diplomacy. I doubt Hadrian would have anything against it either [but if he is taking over just for 1 turn no one can blame him for ignoring any diplomatic messages as he is in no position to sign anything].
I will admin also not so small game soon, so I will have a taste of that too
