United and Shanghai
 

I have been traveling to Shanghai for 12 years, 2 or 3 times a year to visit my son. For the first time, ever, my husband and I were upgraded to business class, for free. I had prepaid economy plus and I am only a silver member. How can I get this to happen again?
Csilla

Might as well go to vegas and bet it all on black. Better chances than that happening again.

Betting it all on black does not actually give you bad odds, something like a 47-48% chance.

You must have lucked out because they oversold the coach cabin or they needed your seats, or something like that. At least 10 years ago I was asked at the gate for a UA flight if I would be willing to give up my seat so that a family could sit together and I said no problem, and the gate agent then surprisingly upgraded me to first. But it hasn't happened since. The only way you can "get this to happen again" is to use your miles or GPU's.

Exactly! I know the odds was just saying that all on black is way better than 1 in 24-36 ;-)

Got it, but OP was referring to getting upgraded "for free" - meaning she didn't use any miles, GPU or pay anything, she just got a free upgrade. Chances of that happening (on two tickets no less) are far less than 1 in 24-36. (Unless I am misreading her original post)