About 10 years ago, I had to fly from ORD to AUS with my two bags and two heavy boxes (3 cases of wine, carefully repacked -- long story involving a fully-Kosher family wedding in Texas). Excess baggage charges on UA would have been around $275.

A friend dropped me to the airport. I got out of the passenger side and opened the trunk. I handed the Skycap my ticket with a $50 bill on top and said "all four need to go to Austin with me."

He looked straight at me, looked at my friend and loudly said, "Fine, I only need to see one of the tickets" and checked all four items through.