I'm sure a few of you knew about a few signed books that have popped up here and there, as advertised, last holiday season (Anna Kendrick, Amy Schumer, etc). But I'm curious if anyone has stumbled upon signed books that haven't been advertised as such - i.e. don't have a "Signed Copy" sticker or any other indication of being signed.

I was randomly looking through the book section tonight, and I picked up the new Maddie Ziegler to take a look, and I noticed that they were all hand-signed in blue ball-point pen. At first, I thought it might be an autopen. But the signatures were all different. There was no sign or sticker suggesting they were signed copies. Just curious if anyone else has run across "surprise" autographs like this.