Originally Posted by
mre5765
The flight/route you want to take that day costs $X, but the flight you've booked costs $Y, where Y is much less than X.
A 1K can stand by for free, take flight Y but it it for $X.
Why do I want to take flight Y and not X?
- Schedule: I get there sooner
- Better seat (fewer seats assigned in economy so more comfortable ride, or more F seats so better chance of an upgrade clearing)
With the UDU, when I walked up to the gate once a while trying to stand-by on an earlier flight, I usually was told that F is checked in full and ended up sticking with my original flight that was already upgraded. YMMV.