As any real Constitutional scholar (as opposed to those "lecturers" from UofC) It is precisely representatives of the federal government who are most constrained by those "little signs" whether they be NO SOLICITING or NO TRESSPASSING or DON'T FART ON MY PROPERTY.
Constitutional Law 101 (you can impress your friends over at Kos with this one) the Constitution does not grant rights, it constrains the Feds from encroaching on them. Further, it recognizes autonomy, State Sovereignty and home rule. Those "little signs" carry the full weight of the law, and a Federal Agent encroaching on them risks arrest by local authorities.
This is the principle behind the enforcement provisions of the various State Firearms Freedom acts currently being codified.
But that's neither here nor there. What we really want to know is, "How's the water under that bridge?"
