In some cases a defendant is not liable for trespass even though she has intruded onto another's property. Public officials, for example, do not have any special right to trespass, but a housing inspector with a SEARCH WARRANT can enter someone's building whether the owner consents or not. A police officer can pursue a criminal across private property without liability for trespass. The police officer's defense to a claim of trespass is her lawful authority to enter.
A hotel employee who enters a guest's room to perform housekeeping services is not a trespasser because it is customary to assume that guests want such services. If charged with trespass by the guest, the hotel would claim the guest consented to the employee's entry.
A landlord does not have the right to enter a tenant's apartment whenever the landlord wants. However, the landlord usually has the right to enter to make repairs. The landlord must arrange a reasonable time for the repairs, but the tenant's consent to this arrangement is either contained in the lease or is implied from the landlord's assumption of responsibility for making repairs inside the apartment.
A person is not guilty of trespass if he goes onto another's land to protect life or property during an emergency. For example, a passerby who sees someone pointing a gun at another person may cross onto the property and subdue the person with the gun. Someone at the scene of a traffic accident may go onto private property to pull a victim from one of the vehicles.
Permission to enter someone else's property can be given either by consent or by license. Consent simply means giving permission or allowing another onto the land. For example, a person who lets neighborhood children play in her yard has given consent. Consent may be implied from all the circumstances. A homeowner who calls a house painter and asks for an estimate cannot later complain that the painter trespassed by coming into her yard.
Sometimes consent to enter another's land is called a license, or legal permission. This license is not necessarily a certificate and may be in the form of a written agreement. For example, an electric company might have a license to enter private property to maintain electrical lines or to read the electric meter. The employees cannot act unreasonably when they make repairs, and they and the company are liable for any damage they cause to the property.