Nonnie, if you want to walk barefoot, do it, don't worry about FMIL. Ditch the carept!! If you want the sand between your toes on your wedding day, you will regret it if you don't.
rgonzalez_83, I would have someone who thought they were going to be in the weding do the Sand Ceremony reading, or have them kinda "in charge" of making sure everything is running smoothly before and after the actual ceremony. It will sorta make them feel like they have an inportant role. Thats just a thought.