Hi Tim
I agree posters should give some indication of who they are, but he/she is laying the glove down basically and challenging someone to come up with ANY evidence that border morris specifically is related in some way to minstrelsy.

I know of several seasonal customs involving dance that are directly connected to minstrelsy but I have no evidence personally to link border morris.

In view of the difficulties being described here would it not be enough for those customs/teams not linked to minstrelsy to carry with them a sandwich board stating that?