I would theorize that for it to be discrimination you would need to prove that you are entitled to that jumpseat. Since the jumpseat is at the captain's discretion that would rule out discrimination. The other argument against discrimination is that there appears to be evidence of jumpseaters, albeit few, who have caused a distraction to the crew by various acts done while the aircraft was being operated. Since, as far as I know, the evidence appears to have only come from US Airways pilots, there is no reason to need to apply it to other pilots not employed by US Airways. (Note that I did not say East pilots or West pilots, but rather the entire pilot workforce at US Airways.)
The best solution, IMO, would be for all US Airways pilots to behave like adults and respect the wishes of the captain, whether he/she asks for no union or company business to be discussed or to allow it up until the captain asks for the topic(s) to be dropped. However, since by the time the latter may take place the flight crew may be agitated and distracted, there may be a valid argument to be made for no discussions of union or company business at all. Finally, there is no reason at all for any "gotcha" behavior of any kind on the flight deck.
