It's a lot of fun. First, some tips:
1) Make a PS and ask them to note "rehitching ceremony" on it. Most likely the CM taking the PS will NOT know what you are talking about. That's ok -- just politely ask them to type "rehitching ceremony" in the Notes section of the PS.
2) When you check-in at Garden Grill (this is the only restaurant that does the ceremony), tell the CM you want to do the rehitching ceremony. They will note it on your server's card.
3) Enjoy!
The ceremony is done after your meal. Your server acts as the "justice of the peace". You exchange very simple "I do's" (again) and then the fun part -- you kiss while everyone counts to 100!
(They count 1, 2, 3... to 10, then 10, 20, 30... and so on until 100!

)
When my DW and I did this, we received a complimentary cake and a certificate. Sometimes, if available, the characters may participate. It depends on the time you schedule the meal, how busy the restaurant is, etc.
Some people reported that the CM forgot to do this. If that happens, just remind them. I recommend making your PS for an off-peak time ... better chance of getting the characters involved and your server not being so busy he/she forgets about this.