Interesting. What are the odds of this?

Back when I was busting tires and changing oil at Target (early 80's), we had a guy come in for new shocks for his blue Chevy (something). About the exact same time we had another customer ask for an oil change, for another blue Chevy.

Same keys, both blue Chevy's...

Long story short: The customer who wanted just the shocks got a free oil change, and we only noticed it because we didn't have the shocks for other Chevy.