Mysterious $15,000 Diamond Ring Gift

A Westborough, Mass. man says he returned to his unlocked car after work to find someone had left a little box with a ring inside on his seat with a note that read:
“Merry Christmas. Thank you for leaving your car door unlocked. Instead of stealing your car I gave you a present. Hopefully this will land in the hands of someone you love, for my love is gone now.”
MSNBC article
Awwww! What a touching Christmas story. You know, something like this happened to me once years ago. My ex-husband and I had just split. One morning, I went to my car and found I'd forgotten to lock it the night before. Just like the guy who found the gift on his seat, there was a gift for me on my seat too! Only it wasn't a $15,000 ring. Instead, I was blessed with an old country music cassette tape. I popped it into my tape deck just for giggles and heard the lyrics “All My Ex's Live in Texas” which was enough to instantly repulse me. I quickly hit the eject button, tossed the gift on the floorboard, and went about my business.
Was it some kind of message from my ex? A practical joke? Or was it just left there by some kid who was looking for valuables and upon finding absolutely nothing worth taking, not even the car itself, left it as a booby prize? Alas, we'll never know the answer to this, one of life's little mysteries. Some people find big $$ items like diamond rings left in their car, some people find crap. Such is life.
Note to ex: I'll never move to Texas.