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 Georgia, property owners can use 'No Trespassing' signs to deter unauthorized entry and limit liability. Under Georgia law, specifically O.C.G.A. § 16-7-21, criminal trespass occurs when a person knowingly enters the land of another without permission or after receiving notice to depart. Posting 'No Trespassing' signs clearly and conspicuously can serve as such notice, making it easier to prove that a trespasser had knowledge that they were entering private property without permission. Regarding liability, Georgia follows the general rule that landowners owe a lower duty of care to trespassers than to invitees or licensees. By posting 'No Trespassing' signs, landowners may further reduce the risk of being held liable for injuries a trespasser might sustain on their property, as the signs can demonstrate that the trespasser assumed the risk by entering the property against the owner's warning.