About 15 years ago, when I was doing Tier II Tech for T-mobile, I had a customer offer me $10K because I fixed his Blackberry while he was roaming in Europe. So stuff like that CAN happen even to the least expecting person...
Damon.
The difference here, is that you were interacting directly
with the customer. We see Customer reps maybe in final assembly or over certain critical repair or modification work, but there's nothing for them to influence at my level, that can't be better handled by a word to the liaison who doesn't come down where we are.
to put this into perspective for you, I'm vanishingly unlikely to see or be offered a ten thousand dollar tip for what I do-the customers are unlikely to ever look at the heavy structure under the panels and go "Yeah, wow, that blend and rotopeen is ****** amazing, it's really going to help prevent stress cracks..."
much more likely, is if they're looking that deep, "Who is the dumb jackass who let a rivet-die mis-strike generate stress cracks in my airplane? how was this not caught by your quality control people? we're going to Airbus!"
see the difference? If I do MY work right, or well, nobody should be able to tell, because everything works correctly. what you did, is specialty correction of someone else's mistake (possibly even the customer himself) on something he looks at and uses every day for both business and personal use.
given the dollars you cite in your post, that ten grand was to that customer about like me giving five bucks to the coffee girl as a tip-something done off-hand and off-the-books and not thought about real hard, you see?