I'm just a lowly Silver but this is the first time I've had any kind of status so this is all quite new to me. So the other day on my return from a trip to Asia, I was surprised that I was able to score an upgrade from economy to business on NH1010. I was connecting in NRT from BKK so I had my boarding pass from UA882 with the *S / Premier Silver visible on top. I noticed the GA for NH1010 wasn't busy so armed with my boarding pass and passport I politely inquired if there were any upgrades available for my flight. She took a look at my BP/passport and she proceeded to print out a new BP with an upgrade to C! I thanked her graciously and thought to myself "wow, Silver is amazing - I look forward to flying in C all the time!"

Now that I'm back, I've spent the past few days reading up on FT to learn how to take advantage of all my plentiful Silver benefits/perks. The more I read, the more it seems like my upgrade might have been an exception rather than the rule. Did I just get lucky and catch the GA in a good mood? Or, can I expect a reasonable chance for last second gate upgrades in the future if the flight isn't full? I'm guessing if I'm flying on UA and there's availability I'd get a CPU, but how does it normally work with *A partners?

Here are some additional details if it matters:
-I was traveling solo
-Both UA882 and NH1010 were booked as V
-I booked on United.com
-I received 100% PQM even though the itinerary stated 70%
-C cabin was maybe 1/2 full

Thanks!