Love how it takes them 3-5 business days to return the money they stole from you.
We had to remove our credit card from our account because Amazon kept charging us for Prime and I would have to call them to get it cancelled and refunded (and wait 3-5 business days to get our money back).
We were very careful when checking out that we didn't have anything checked saying "sign me up for Prime", even had it happen on a day where we did not place an order (and therefore weren't on the site) for at least a week on either side of us "signing up for Prime." Once we took the card off the account it stopped happening, so it wasn't anything we were activating.
It's annoying to have to re-enter our card information if we want to order something, but less annoying than having to call them every month to cancel Prime again. And anything that increases the barrier to using Amazon is probably a good thing anyway.