Katherine
Back in the Medium days when The Atlantic was posting articles on Medium, there was one article from the Atlantic that was quite interesting. Apparently, there was (is?) a small cadre of left-wing bloggers who were posing as right-wing thinkers and posting on right-wing websites. They would tailor their messages such that 1) they would not get kicked out and 2) just get right-wing people to think a little bit about their values. They would write comments like: "Be careful. The lib-turds are setting up fake stop-the-steal website to get your money."
I give high commendations to these people.
But the billboards are a good idea. Hard for the libertarians to miss them. But then again, libertarians don't use roads, right?