I have an employee that tells me this story every time I mentioned it was an oil change weekend (I tend to do 5 trucks at a time). It has never happened to me but he still tells me to always check for the old gasket.
I did have a similar lesson with an Alfa Romeo Milano. The oil filter threaded shaft came out of the block with the old filter. I naively screwed it to the new filter and screwed it back into the block only to find it was not as tight as it needed to be. Seven quarts left a nice stripe down my block that I got to look at as I pushed the car back home. Luckily the stripe started about 50 feet from my house so it didn't lead back to the garage where the screw up started.