“Near Boulder, CO I have rarely had a political sign last over a day.”
Get some cheap rubber gloves, and rub your signs well with poison ivy. That way, the thief will at least be made very uncomfortable. Check out your neighbors for Calamine Lotion! That’s how I found out my neighbor’s teenager was the culprit in my case! “Gee Joe! That’s a nasty case of Poison Ivy!” Bwaaaaa!
I would never put a sign in my yard or on my vehicle. That would be asking for trouble that I could not put a permanant stop to if I am not at home or near my vehicle. When I retire I may take that crimminal incarceration process up as a hobby on my property. I have put signs up high on trees in the right-of-way by the road using a ladder and leftists get up there and rip them down. By the side of the road they last maybe 3 hours and are gone, replaced with a Zer0 sign in the same spot.
+1