I pulled a "Rudi" in ALB last month and after NW re-assigned my flight to HKG on UA (after a weather-related cancellation) I gave the UA agent a box of European chocolates for his assistance in getting my wife and I exit row seats (we were flying coach with a NW vacation package). He couldn't assign seats for the NRT-HKG segment and told us to try our luck in NRT. Once there, we were paged almost immediately and given BC upgrades for the remaining flight. Luck or chocolates? You judge.
I now travel with a supply of chocolates ready to be handed out to those wonderful GA's.