When you're walking into the store, do you take in a cart that you pass which is not in the corral, or do you shake your head and curse whoever left it there, while leaving it there yourself, to get one at the door? Also, you could take one in from the corral, or you could return the one you used back to the front of the store, instead of the corral.
Taking it to the corral is not the only measure of a "good" person. Why don't you do even more? Why don't you take several carts from the corral to the store when you're entering? You're heading that way anyway. Because you're not paid to do it, you say?