[Death by Mirrors]

Originally Posted by Kaderin Triste

Tennis balls are typically placed on the legs of a walker so that the elderly who need support while walking, but don't necessarily have the strength or coordination to properly lift a walker can slide it without it snagging on carpets.

Ah, alright - thanks!
Pretty much every elderly person 'round here has the luxury model with four wheels, so I wouldn't have thought about placing something on the legs... but it makes perfect sense. *nods*