Make sure you don't have ANY part of your firearm covered, not even by a holster. That's what AG Van Hollen's office says is "concealed". I talked to his office about it June 16th. They say they have case law going back to the 30's defining concealed as "any part of the firearm covered", and yes they even said a properly OWB holstered weapon is considered concealed.
If by chance he shows up, ask him,
"In your memo you said open carry is legal in Wisconsin, but please sir tell me, without Velcro or double sided tape, how can I open carry legally?"
I really do hope you all have a great turnout and a fantastic day. It's a great thing your doing.