You clearly don't have a grasp on what pilots do and why BC or FC for deadheading is important. Let me give you a personal example.
I'm furloughed and with another airline right now, but this applies across the board. Last year, I was on reserve in LA, and was called out to DH to Hong Kong via Tipei. Total time of DH in coach, 22 hrs, got to HK, give block to block 10 hrs rest and fly out that night back to the States. Having gotten stuck in coach, I couldn't get any restful sleep, and when I got to HK, it was late morning going into the afternoon. Try to get to bed, but only got around 6 hrs of sleep, body clock was totally messed up. Then had to delay the flight by 4 hrs so I could get the rest I needed. Finally we left around 4 hours late and I still felt tired on the flight back to the States. This is a typical example of international ops and hence the importance of the BC or FC seat, even if you have a rest period coming at your destination. Now, not to sound mean, who do you want to be well rested, the flt attendant who is going to serve the drinks in the back or the pilots who need to be alert to fly the aircraft, especially in international operations? Senority should have nothing to do with it, it should be strictly by rank on DHing.