I've never maintained an online wish list. My first online wish list was registered with Amazon.ca. It's pretty much just a list of photography reference books that I would like to have to hone my skills.
For Christmas I received one of those books, Digital Wedding Photography - I figured that I needed to pop in there and take it off my list. I signed in today and noticed it wasn't on my Amazon list, so I checked my Chapters list, it wasn't there either. Going back to the Amazon list, I poked around a little. (I was advised the book came from Amazon). There's an option on the Amazon wish list to show you purchased items on the list.
I checked to see what was on the list of purchased items, and there was another book there that had been purchased, but it's on back order. No surprise for me (luckily I don't often add/update the wish list).
Anyhow - for anyone that would like to maintain the surprise, you should avoid purchasing through the wish list. Just grab the ISBN number of the books and purchase through your own account (close the browser window and reopen).
Oops. I'm looking forward to getting the second title though!