Our Tscos has a boundary blocker too. There is usually a gaggle of disconsolate trolleys sitting as near as they can squeeze to the cut-off point, abandoned by shoppers pushing their stuff towards the bus stop.
Their are several clear plastic trolley shelters scattered around the car park. They each contain half-a-dozen trolleys, all at weird angles to each other and filling the whole space, while at least a dozen others stand around nearby in parking spaces. It only takes one more push for the second comer to push theirs in to spoon with the first, and so on for the rest, but most people seem to prefer to leave them in the rain.