I posted earlier that we used the silicone bracelets successfully (putting the 2yo's on his ankle).
I picked the bracelets over other forms of id because of its versitility and reusability.
Dog tags need to be attached to something as do shoe ids, etc. My kids are wearing
Crocs and sandals most of the time in the parks and neither work w/ anything attached to them.
The bracelets are waterproof so they aren't an issue on wet rides or the water parks. They don't have a ton of space on them, but I only wanted our cell numbers...I don't want to broadcast my kid's names.
We ordered ours from Sharene and were able to put the following on them:
If Lost call my mom at ##### (cell)
If Lost call my dad at ##### (cell)
I ordered four (one for each and then a back up for each) and the total, including shipping, was less than $12. We received them in less than a week.
In addition to the bracelets, we played find the CM every day at various times. Dd (6.5yo) really liked the "game" and it helped her figure out who was and wasn't a CM (since they are always wearing different things).
I really think that the bracelets were the way to go for us. Our trip was in December and we've been able to use them again and again since then at museums, carnivals, the zoo and most recently ...the beach!