I like the OGR hat concept.
It would be easier to spot in the hall and move over to meet someone ( you knew or didnt know).
It would need to be a nice smooth color and not some gaudy color. (Sorry but the orange and blue colors are great on lionel boxes but on clothing you stick out everywhere you go, IMHO).
A hat would probably be much cheaper and easier to get the right size.
You could also wear to other train shows and maybe entice some questions about its origin, especially if the hat was really attractive and fetching.
Might be people ask where you got the hat, which would open up a conversation to get them to join OGR.
If it were hats it would be much easier for OGR to bring them to York and sell them to us. Much lighter than clothing and one size fits all.