We also have aldi/lidl here. I think the lidl mechanism is identical in the US though, since the quarter works in it. (try a €2 some time, if you have one) Rea

We also have aldi/lidl here. I think the lidl mechanism is identical in the US though, since the quarter works in it. (try a €2 some time, if you have one) Really you only have to walk to any other cart to get your coin back, and I think it being a loss aversion thing makes it feel like more than just paying 25 cents. Also, anyone parking up is likely to grab abandoned carts with the coin in them for their own shopping.