The other rule tied to this one was no barefeet were allowed on the carpet either. We always had to have socks on. It wasn't until recently I realized the reason for the rule and, when we move, or the next time I get my carpets clean, I'm going to implement this rule in my house.
Think of where you walk in your shoes (public restrooms, grass where animals have been, etc) and then think of all the stuff that gets stuck to your shoes then transfers to your carpet. My carpets look so dingy right now and it is because we just walk all over the carpet in our shoes throughout the day. The reason we had to wear socks was so our body oils didn't get on the carpet. If the oils are on the carpet then dirt has something to stick too.
When I look at how dirty the water is when I clean my carpets it is incentive to remove shoes before walking on carpet. Plus, it means I can go longer between cleanings too. So, the next time you come to my house and I hand you some booties to put over your shoes you can thank my Dad for the idea.
What rules house rules did you think were stupid only to determine later on that they weren't so bad afterall and have implemented them in your own home?