Thanks for sharing your opinion.
As I asked and you failed to answer...Do you need a sign telling you not to vandalize the property of others?
That of course is a rhetorical question. The issue isn’t telling others what they should or shouldn’t do, the issue is warning those who decide to trespass on your property.
What I’m saying isn’t my opinion, it’s actually the common law, formed over many hundreds of years.
My opinion is I think this portion of the common law is reasonable.