"Please remove muddy footwear"

While seeing my sister in Dorset, I visited a pub with a sign that said "Please remove muddy footwear." I can't remember seeing one of those signs in a pub before. It makes sense with a lot of people coming in from country walks. I imagine the stone floor would have been a little uncomfortable to walk on in socks, but I suppose regulars would know to bring a change of footwear if their shoes were going to get muddy.