This is a good habit for any able bodied person to get into. Not only can it help out someone who needs a closer spot, it doesn't even cost you time on average since you're less likely to be held up by traffic getting in or out of the spot. Plus adding a little more walking into the day is healthy.

I always shake my head at healthy people who block the traffic lane for minutes waiting for someone to load groceries and free up a specific spot, when there are dozens of open spots 40 ft away. Their laziness isn't even saving them any time or aggravation.