You don't want to see what it looks like with pure seniority space A travel. Imagine you're commuting, and the night before there are 15 seats. You put in for both a jumpseat and a seat in the back.

When you show up to the airport, you all of a sudden see that there are 20 listed for the 15 seats, 3/4 of which are 1990s hires FAs, their 20-year old kids, and their spouses, and a handful of senior captains. You're out of luck for the back of the plane. The jumpseat only shows you, though. You're going to make it!

Then, as you're waiting for a flight to board, a senior captain with a mustache, cell phone holster and tasseled penny loafers shows up at gate. He proceeds to grab the jump seat, and you're left stranded for your commute. The best you might get from him is a "sorry bud, best luck next time".

Many such cases. Don't ask for this, because it's hell.