I've thought about it actually but it would be a pain to carry it along. Sometimes I'll just walk around barefeet.

As a matter of fact, I almost accidently had to ride a century with my sandals. I had thrown my cycling shoes in my gear bag and wore my sandals in the car with the intent on changing at the baggage dropoff. After dropping off my bag, I proceeded to the start line and tried to click into my pedals... ewps! I sheepishly went back to the gear truck and asked if I could retrieve my bag for a second. The guy loading the truck waved me in so I could find my bag among the 4000 or so other bags and shouted out to the crowd, "MAKE SURE YOU HAVE EVERYTHING YOU NEED FOR THE RIDE OUT OF YOUR BAG BEFORE YOU HAND IT TO US!" I was a little more than embarassed at that point.