Yep, at least four times! Back in highschool, with just MK there at the time, ran into a classmate, then in college I ran into a friend of my roommate's. Then, in 2000, when I surprised my DD, 9 at the time, with a trip to WDW, we ran into a classmate of hers waiting in line for the bus at Epcot. She was so shocked! The last time was in 2007. Both of us work at our local library. All of a sudden, I said hey, isn't that the kid who comes in the library sometimes? She says nope, but I was sure it was and he kept looking at me like he recognized me, too. Then I saw his mom in the line for the ride walking a bit in front of him. Then I knew it was them and she saw us, too, and we laughed at what a small world it was. What ride was it? Why, it was It's a Small World, of course!

Now that kid and my DD are good friends, lol.
Last year at SSW we recognized a Disser that I'd read trip reports from and that was fun! You know, back in 07 there was a couple we knew was going and we were more surprised that we never saw them actually, lol!