Some months back my local Wally World removed all of the farthest-out cart racks from their mammoth parking lot. The rate of cart abandonment sky-rocketed, with carts drifting all over the far reaches of the lot. Then a couple of weeks ago they relented and replaced the rural cart racks. Abandonments went way down. There have to be enough cart racks that customers don’t have to hike a quarter-mile to do the right thing. There must be some sort of sweet spot. Perhaps that could be the author’s next research project. He could even apply for a grant from a big-box store.
It does seem to be a function of cart corral proximity: if there are many such corrals, they do (in my unscientific survey) seem to be used more frequently. My go-to market has more than the usual, and only very rarely (almost never?) do I see a renegade cart. At the Bargain Hut in my town, the corral/parking space ratio and the number of feral carts are both much higher.
Also, I love Free Republic for exactly this kind of intellectual stimulation...