The easy answer is to make these shoes unavailable, and possibly restrict your cat to an area of the house where she can coexist with the bipeds.
There was a time early in my career that I was a strict behaviorist, believing that felines did things strictly by instinct; and that these problems could be easily remedied if I applied common-sense psychology to them. Now I am convinced that some cats do things out of spite. I'm going on a limb here, and will state that I bet your mother and feline do not get along.
If that is the case, then rapproachment is indicated: let your mother feed the cat, groom her, etc. Cats can make life miserable for those that abhor them. If this is way off the mark, then my apologies. But I would still make the shoes unavailable and restrict your cat's range to a quiet area.
Dr. Van Lienden
Dr. Raymond Van Lienden DVM
The Animal Clinic of Clifton
12702 Chapel Road, Clifton
Virginia, U.S.A. 20124