What's the consequence of crossing a picket line..? Personally I can see myself just riding past them honking and flipping em the bird for holding me up.
I don't think there's a legal issue with crossing a picket line, the issue comes from the almost inevitable moment when a picketer decides that they should interfere with your crossing the line (their stated objective in manning it). Someone gets hurt, even slightly, and then there are the legal and insurance hassles that follow.