I have no answer to the OP's question about signage.
But the following discussion about LEO's & such,, especially the negative stuff,, is heartbreaking for me.
My youngest is a LEO.
I've had to give him an ear & shoulder to cry upon when he tried hard to save the life of a little girl, who was shot by another child, because stupid adults failed to secure a shotgun. And I've had to attend the funeral of one of his good LEO friends who was ambushed by a thief,, and shot dead just trying to do his job at stopping a thief.
I also have a State Trooper friend who, on July 3rd, 2023 saw a broken down car on the side of an exit ramp. He stopped to offer friendly assistance. Never even asked the guy for an ID or made any attempts to accuse him of any crime etc. He called the "Emergency Roadside Assistance" truck for him. Yet,, suddenly the guy came out a car with a Desert Eagle .44 mag & shot my friend point blank in the chest. Totally unprovoked. Luckily my friend had on a vest,, (that wasn't rated for a .44 mag,) and was able to return fire to defend himself. I shared that story here in July of 2023,, under the title of something like "My heart stopped" .
And I know a lot of really good people who believe in the law,, and became LEO's to try & help others. I've been around LEO's all my life. Proudly.
Yes,, I will admit that it doesn't matter what organization, group, club, or whatever,, will ALL have bad people in them. Catholic priests, BSA leaders, LEO's, etc.
But it truly upsets me when I see people curse,, or spit on, or demand defunding or whatever the police,, yet scream the loudest when they are violated by robbery, rape, murder, etc demanding that the police "arrest the criminals"!
I'm sure most of use around here can relate a negative story or two about bad cops. But if the same people are honest,, they can also relate just as many good stories about the police.
And without laws,, and those who enforce them, we'd all have to live in a manner that could cause a lot more lives to be lost. Especially innocent lives,, because of how some people would just shoot someone because they didn't like something. Or they would just steal, rape, burn etc others because w/o LEO's,, they would have no fear of anything except others who might do them harm for doing their crimes.
As Dirty Harry said in one of his movies,, (I think it was Magnum Force,) where he said; "I hate the system, but it's all we got. And until someone fixes it,, I'll follow it!" (Or something like that. )