|We have hardwood floors and no rugs. Not by choice, though by neccessity. See, we have 2 older cats that will pee on anything soft. Rugs, towels, clothing, etc. It's definitely incentive to keep the house picked up.
Maybe they want some soft toilet paper in the litter box?!?!
After a lot of debate, we'll take up the carpet on the stairs, add a hand rail or two for safety (there are none), and see how it goes. If is is really bad, I'll put a wool runner down (much of the cost for putting a healthy rug down on our stairs would be labor and healthier padding, too.)