No trespassing signs can be useful to property owners—especially on large tracts of land or land that is not developed—to put persons entering the property on notice that the property is private property and if they do not have permission to enter, they may be committing civil and criminal offenses related to trespassing. In some states notice is required for a trespasser to have civil or criminal liability for entering the property without permission.

No trespassing signs may also protect a landowner against liability to a trespasser, as a lower duty of care is owed to trespassers in some states, and putting a person entering the property on notice that they are trespassing may strengthen the property owner’s defense against any liability claims if the trespasser is injured on the property.

In Tennessee, property owners can use 'no trespassing' signs to deter unauthorized entry and reduce liability. Under Tennessee Code Annotated § 39-14-405, a person who enters or remains on property without consent can be charged with criminal trespass if they are aware that entry was forbidden or if they are notified to depart but fail to do so. Posting 'no trespassing' signs conspicuously can serve as adequate notice that entry is forbidden. Regarding liability, Tennessee follows the traditional common law approach where landowners owe a lower duty of care to trespassers compared to invitees or licensees. This means that if a trespasser is injured on the property, the landowner may have a stronger defense against liability claims, especially if the trespasser was clearly warned against entering the property through posted signs. However, landowners may still be liable for willful or wanton injury to trespassers. It is advisable for property owners to post clear and visible 'no trespassing' signs to establish this notice and to consult with an attorney for specific legal advice tailored to their situation.