For us its more of a conversation piece, people see them, stop and strike up a chat, and another friendship is formed, if anyone asked us if they could use our chairs when we weren't using them the answer would be a smile and be our guest.
We seen several of them there on our prior trips and met some great folks and thought they were a great idea
Have not made any special shirts for any trips in the past but something I hope to make up before next trip.