What a wonderful story.
It is these types of stories that make you realize that Disney CM's really do try and go out of their way to make a magical moment for the guests!
They do go above and beyond sometimes and it is then you realize how truly special those CMs are.
When we went to WDW back in July with DS, I knew the YOMD was going on, but I didn't expect much. Just typical WDW.
On our second day there, we were at DHS and found out there was going to be a Lightning/Mater meet-n-greet. Since Lightning is DS's absolute favorite character (next to Mickey of course!) we knew we HAD to go see him. Unfortunately, due to weather concerns (lightning in the general vicinity) the meet-n-greet was cancelled at the time we'd showed up for it.

However, we had been chatting with one of the CMs handling the whole thing, a lovely young lady named Rhea. She saw how disappointed we were that it had been cancelled and went to talk to her supervisor. She came back a few minutes later and told us to return at X time for the next meet-n-greet, which was scheduled for some time later in the afternoon.
We didn't know exactly what was going to happen, but we came back when she told us to. She gave DS a little lightwand thing and, with DH's help, let him 'lead' Lightning/Mater into the greeting area.

When she cued the cars to start up, you could see DS's eyes get HUGE and he was so excited. I heard him yell "RACECAR! RAAAAAAACECAAAAAAR!" and got tears in my eyes.
The next day, we ran into Rhea AGAIN

and this time she was working the Sorceror Mickey greet inside the Magic of Disney Animation.
Rhea..I hope you're reading this. Or somebody can pass it along to you. You made our vacation very special, you and your fellow CMs.

We are eternally grateful.