Used to be MBS PremExec
Join Date: Sep 2000
Location: Saginaw, MI (MBS)
Programs: UA 1K 1.9MM, Marriott Titanium w/Lifetime Plat, Hilton LIfetime ♢, National Exec, Amex Plat
Posts: 5,720
Definitely go out empty, unless Y is oversold.
Unlike domestic flights, they'd rather the seats go empty than get people in the habit of hoping for a complimentary upgrade.
That being said, UA will take any revenue they can get...Watch for diminishing upgrades for cash, which may or may not get cheaper as flight time grows closer.