The famous bootprint photo was a planned soil mechanics experiment suggested by David Carrier of JSC. Buzz chose an undisturbed location and took the photo and was careful not to step on it. (I don't know if the crew was careful to avoid it for the rest of the mission.)
I wonder if Neil & Buzz themselves bothered to protect the first print by not treading on it, once Neil photographed it. Of course we only have his word it was actually the *first*. Perhaps, after a few mins he thought "darn, I forgot to photograph it, which one was it?"