I've got a sneaker fetish, too.
I developped my two fetishes during quite the same period of my childhood. Maybe it's about the rubber being kind of a common denominator of balloons and kicks.
Just as I've always avoided contact to balloons, I have a real problem wearing sneaks and sport shoes. There are only some special ones that are not so popular and no eye-catching that I can wear without immediately feeling ashamed in public. Nobody thinks that, but this puts you in really difficult and arkward situations if you come everywhere wearing leather shoes actually intended for suits... (eg to school, dancing in clubs or you for hanging out with friends)
This makes fetishes for me quite difficult. B/c of thsi I also had to come out to my mom aobut my fetishes after she bought me a pair of sneakers. That was really difficult! Hoping for better times when living alone