First question, did they bring you the whole jar, how were you able to see an expiration date.
Was it previously opened?
I ask this because if it was a new jar, had just been opened, it was probably sitting in a store room and I wouldn't worry about the exp. date all that much,
except for the fact that it doesn't shine a real good light on the facility.
But after my preconceptions about mayo, it seems that it is alot safer than the product of many years ago, or homemade.
Alot of expiration dates have more to do with the manufacturers idea of best flavor by, as compared to unsafe to use after.
Just like your born on date on a can of Bud. It might not taste as good as they think it should after that date, but 20 years from now it's still a can of beer.
Or maybe was it served warm in a nice little compote cup?
No telling how it was handled, but I think a nice restaurant might serve the sauce slightly warmed as compared to ice cold for a nice piece of meat.
But nonetheless, if it wasn't sitting there bubbling like it was fermenting, I'm going to guess you're ok.