Question: Say someone took a sign and displayed it by the road nearby hotels saying "Beware: Possible Police Sting Operations." Staying on the public sidewalk and not going into any business private property, would this be protected free speech? Or possible obstruction? Originally Posted by TylerDFight1Obstruction. It's just like flashing your high beams at another car warning them of a speed trap. If another cop sees you do that, you can be ticketed for Obstruction.