Originally Posted by
Chinatrvl
It's not called "a smile", but it's called "a bribe".
I have only once in more than 100 flights witnessed somebody trying to self-upgrade to first on NDG-PVG and later offering money to the purser - he was promptly escorted back to economy. If I, usually in flying first, would witness a purser accepting such a bribe, I would raise quite a stink.
Bottom line is, bribing is not the way to obtain an upgrade.
At the check in counter (not on the airplane), ask if you can upgrade. I'm not sure if the airline or the CSR keeps the money, but it's usually not that expensive (I'm talking about domestic travel here; I've never flown MU internationally apart from Japan).