Originally Posted by
ToneDaBass
mherdeg – If what you say is true, that the answer is truly unknown, then I'm surprised nobody has tried this at least on a short domestic one-way, just to see if it works.
No one has ever reported that it has worked. That either means that (1) it doesn't work or (2) it works but they're keeping it on the down low because it's against UA's rules and it's not supposed to work.
I actually thought that was a pretty good idea.
Giving someone else your other boarding pass is a pretty bad idea for them, could work out OK for you. That other person "stuck in economy minus who got your economy plus boarding pass" will be counted as never having boarded the flight, and their downline flights will all be cancelled. Bad times for them.