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 Vermont, the use of 'no trespassing' signs is recognized as a method for property owners to communicate that entry onto their land without permission is prohibited. Vermont law requires that property owners post such signs or paint specific markings to give notice to potential trespassers. According to Vermont's statutes, if a person enters or remains on the land after being directly or indirectly informed they are not to do so (e.g., by signage), they may be guilty of trespassing, which can carry both civil and criminal penalties. Furthermore, Vermont adheres to the common law principle that a lower duty of care is owed to trespassers compared to invitees or licensees. This means that if a trespasser is injured on the property, the owner may have a stronger defense against liability claims, especially if proper notice of no trespassing was provided. It is important for property owners to understand and comply with the specific requirements for posting no trespassing signs to ensure they are legally enforceable.