I've said this before but I'll say it again. I'm a controller and I'm lazy. I'll sort the aeroplanes out in whatever order sorts the traffic situation bastest - I want the aeroplanes off my frequency as quickly as possible! Don't much care whether they're on stand or on someone else's frequency, I just want to not have to worry about them. I know quite a few other controllers, heck, I even work with a bunch of them, and I don't want to besmirch their reputation too but they all seem the same as me.
To sort the aeroplanes out in any other way than that which suits the traffic situation is asking to create problems for everyone! And it may not be PC but it's not professional either.
Yup, I welcome an upgrade or a wait in a lounge to which, strictly speaking, I have no entitlement to go in if someone from the airline sees fit. Yup, I'll remember the experience kindly. And if an aircraft can get a direct routing or whatever might be welcomed I'll offer it or sort it if I can. If the traffic doesn't suit the DCT or whatever, the aircraft won't get it. But it won't make any difference whether I got an upgrade from that particular operator.