I've never had a pin stolen at Disneyland Paris, I nearly lost one in Star Tours once because it was on my bag and got stuck in the netting of the bag holders in there, but that's hardly anyone's fault.
I've luckily never been pickpocketted in DLP (and hopefully I never will be!) BUT I have had an umbrella stolen a couple of years ago.
I had hung it from the back of my chair in Annette's, and when we went to leave it was suddenly gone.
Very uncool, because it wasn't a cheap umbrella either XD
Ever since I put my umbrella on my chair first and my coat over it rather than the other way around.