Honestly, we stumbled into it. It was our 12 yr anniversary, and my BIL/SIL leaked that info to the server (as they had at EVERY MEAL that day!) THey figured usual deal -- maybe some applause, or a hug from Mickey, etc. Next thing we knew, the servers were asking us to stand up and re-take our vows. Mickey was there (as witness? Minister? CAn't recall -- it was REALLY fast!) THey said some words (mostly amusing -- I know DH and I were laughing, because at one pt they asked why we were laughing, this was "serious" stuff!), then asked us to repeat in the appropriate places "I do", then told us to seal the deal we had to lock lips for 100 seconds (which promptly turned my dh a lovely shade of crimson embarrasment!) They then gave us a little cake, I believe (well, correct that -- maybe it wasn't so little, because I recall splitting with our entire party of 12). I think we have a certificate too -- though at the moment I can't recall where the bugger it might be...
I have read of others asking for the re-hitching and either (a) getting similar treatment, and (b) getting little or nothing, or even bad attitude... I think it depends heavily upon your serving staff that night and the humor they are in. On the night we went, we were already getting HUGE amounts of attention from the characters... we got the impression that there were not very many patrons that night (though I know most of the tables near us had folks seated at them). Or maybe it was because we were a party of 12 and had "guaranteed 15% tip or more!" written on our foreheads -- who knows!?! I guess what I'm trying to say is that it doesn't appear to be a set-in-stone plan, or a "given", that they will do this bit for you (which may explain why the CM had no idea!) and those who have reallllly set their hearts on it have sometimes been disappointed. Perhaps others will post after me and give their impressions as well.