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 Nevada, property owners can use 'no trespassing' signs to deter unauthorized entry and reduce liability risks. Under Nevada law, specifically NRS 207.200, it is illegal for any person to willfully go or remain upon any land or enter any building after having been warned by the owner or occupant not to trespass. The warning can be given by posting 'no trespassing' signs at entrances or at intervals of not less than 1,000 feet along the property boundary. These signs must be conspicuous and designed to give actual notice to potential trespassers. The presence of such signs may also limit the property owner's liability in the event a trespasser is injured, as Nevada adheres to the doctrine that a lower duty of care is owed to trespassers compared to invitees or licensees. By clearly marking property boundaries with 'no trespassing' signs, property owners in Nevada can strengthen their defense against liability claims and enforce their property rights against unauthorized entry.