Thank you and karma to you for speaking up, Kindleworm.
It's very easy to buy books accidentally on the Kindle - so much so that Amazon provide a button to cancel accidental purchases and get a refund, or you can call Amazon customer service to do the same thing. I've read elsewhere that it's the biggest reason given by customers for returning Kindle ebooks. It was even discussed a couple of months ago here in Mobileread -
https://www.mobileread.com/forums/showthread.php?t=99517.