One of the problems with the little glass crack pipes that get handed out to people to protect them from infections and stuff is that they break easily. They break into tiny little pieces and bigger pieces and they're a pain to sweep up. I'm not usually an uptight sort of person - you'll often hear me break out into "it's all just molecules" - but it's starting to freak me out when people walk into my house and don't take off their shoes.
My next door neighbours are Chinese and they're all about taking off their shoes. They've got a total system for where the outdoor shoes get to and where the indoor shoes start.
It makes sense. I also like walking around with shoes on. But in my neighbourhood, right before you get to my door, you've walked in dog pee, people pee, barf, poop, and lately, bits of crack pipe glass. So just take off your shoes at the door.
I can see how the eastern tradition of washing your guests' feet when they arrive would also be something to consider taking up here.