I have no policy but ask my daycare families to give me a pair of rain boots if they can to stay here during wet season if we go out and it's raining and they have happened to wear runners that day.

Otherwise my little ones are in bare feet. They all take their socks off when they arrive but my playroom is seperate from the rest of my house ( I also have OCD) When we are in the backyard, I find barefeet are best since they are running around and in and out of the sandbox in the summer.