DD has carried on a lot of pins over the years. She's never had a problem even on the trip she took her whole pin bag which must have a hundred or more pins in it.
I'd never pack something that expensive in my checked bags.
I'm putting mine in my carry-on and was even thinking of wearing them on the plane! I'm going to use DME so I want to have them with me since I plan to head straight to a park as soon as I have my Parkpass!
We always carry them on. It would just be too upsetting if they somehow got lost with the luggage. We also leave any pins at home that are truly special and would never be traded.
I had the same question so when we went down, I put them in my checked bags. I forgot about them on the way home and they were in my carry on and I had no problem.