On a few South East Asian Airlines one would try and bribe an upgrade immediately at check-in... this usually works with a $100 bill being the universal "ticket" required.
Failing that (very rarely and only if the staff were paranoid about being spotted) an in-flight "upgrade" (again at the magic $100) negotiated with the purser does the trick 100% of the time.
At one stage I did this so often I didn't even bother to book Business.
They also treated you damn fine after that
