Howdy Amealnet. I would hazard to guess just past expiring or shortly before, lol
Have a friend in Holland who laughs at me when I send her pics of my builds. She always tells me "only old people ride those" Last year had a guy flag me down in an angry manner who asked me "aren't you a lil old to be ridding that?" I am 44 or 45. Have to ask the baby's Momma.
I really enjoy talking to older folks about MBs. They really appreciate and enjoy seeing them. Will tell you storys about the motorized bicycle they had way back when.
Might just be me but in answer to your question, I say never!