I like this oneWordy - not too good if your visitors are illiterate - but, it IS comprehensive:
WARNING !! DANGER !!
Stop !! Read before proceeding
Utility and delivery personnel are granted safe passage onto this property while performing their duties. All other persons entering this property must hold contract or invitation with owner or tenant granting ingress with indemnity. Any intrusion beyond this point without said contract or invitation will be seen as a clear statement of intent to trespass, extort, harass, oppress, threaten, intimidate, injure, mutilate, molest, or otherwise jeopardize the rights, safety and life of the owner, or tenant.
You are hereby notified that the owner or tenant requires that ALL PUBLIC SERVANTS abide by the The Constitution of the United States of America, and the ratified amendments thereto. Any federal, state, county, city, municipal employee or any other government agent(s), official(s) or person(s) without the above mentioned contract or invitation MUST present a properly prepared warrant as prescribed by Constitutional Amendment IV and XIV, "... and no warrant shall be issued, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized." Alleged zoning or code non-compliance violations do not establish Constitutional reasons for entering this property. Violators will be treated as any other hostile intruders, described above.
Violators may be fined not more than $10,000, imprisoned not more than ten years, or both. U.S.C. Title 18, Sec. 241 & 246.
A person is guilty of criminal trespass if he / she knowingly unlawfully enters upon this property and could place his / her life at risk.