If I am not upgraded to first class, I will almost always settle back in my coach seat and sleep - many times I'm out before take off.
On a flight last Monday MSP-ABQ, I had not slept well the night before and was dozing off before we even left the gate. The plane was full and I was settled in.
I was stirred in my sleep when I thought I heard someone call my first name. I heard a "That's me!" and someone (GA? FA? Don't know) was dealing with a passenger a row behind me.
I went back to sleep, which I did for most of the flight (5A on an A320 is comfy enough)
Earlier today I checked my activity on the NWA website, and, lo and behold, my class flown/paid for that flight is F/L!
It appears someone, not me, grabbed my upgrade for the flight. Shame on me for not paying attention. Shame on him for not 'fessing up that he was not deserving . I don't have an unusual first name, but it does have variations in spelling. Shame on the GA or FA for not confirming the passenger.
Lesson learned? Stay awake until you are off the ground!