It is not uncommon to go to an ATM to get money and forget the used card.
You first put your card in, then choose what you want to do, and last you have to wait for your card to be returned to you.
It is normal to move on once you finished what you wanted to do and only realize you forgot your card once you want to use it again.
A memory leak (or any resource leak) is to forget to return something to its available state once it is no longer in use.