I cracked open a roll of 2010 quarters (Canadian) today and out rolled a blank planchet. My first of any kind.
What are the odds of finding a blank planchet in rolls? I used to work as a cashier in college, and a coworker found one. That's the only one I've ever seen though. The dummy wouldn't give it to me, even though he didn't collect coins. "It's cool, man. I want it." I can only imagine what happened to it as of now.
No ideas as to the odds. This is the first I've seen. I know cent blanks are a lot more common but that could just be because of the quanties of pennies minted.
