I find the lengths that some people want parents with small children to go to pretty ludicrous. I am not putting an infant into a car in -20 weather, unloading the groceries, then dragging the child out into the cold again.
Also, I'd NEVER leave a child in a locked car in Florida in the summer even for 30 seconds to return the cart. It's immediately like an oven in there.
Guess what! You are not entitled to have everyone else put the cart back in the well, just because you want it that way. If stores want a high percentage of their carts returned, they have the power to make it so: Just put lots of cart wells out.
In my Publix in South Florida, I never returned my cart, because there were no corrals, and everyone left their carts out if they hadn't been escorted out. But Publix baggers were very often in the habit of having bag boys take your groceries to the car. They started to phase that out a bit around the time my son was born. But they were out there all the time, and you could normally just hand the cart to them. If not, everyone just put the carts partially on th the little islands, so they wouldn't move and hit anyone's car.
In Michigan, there are a lot of corrals, my son is a lot older, so I return my cart 99.9 percent of the time.
But kids come before carts, people.