I use this when I'm scavenging wood mainly on roadsides never on private property. It helps defuse a situation by pointing to the sign.
Ive thought of doing that. Last Fall when Asplundh was cutting everywhere in the area, i made a "KEEPING WOOD" sign. Id leave it on wood that wasnt in a yard. I was rather brazen i must admit. The one pictured i got permission to take the wood from the homeowner and leave the sign. carried it with me for a couple months and was having a field day scrounging all the wood they cut.