I was in California last year and they had just instituted some new rules that included the brass Mickey and Minnie pins from Hallmark. There was a book at the pin trading area that has a collection of pins that are not tradeable with cast members' lanyards. Many of those pins were from Japan! They were mostly epoxied pins and cheap pins from Europe. They let me trade some of my Hallmark untradables for some of their's as long as they didn't have any of mine as doubles. Don't know if they still do that.
No problem trading Hallmark pins with cast members in Florida last Christmas. Different parks, different rules.
WDW lanyards had more cheap pins that guests traded the cast members as compared to DL/DCA so I see the reasoning behind the rule change.
Funny thing is many DL brass rack pins are technically not tradable with cast members' lanyards at DL/DCA.