Tex. Business & Commerce Code § 91.056

A rental company may not void a damage waiver unless:

(1) an authorized driver causes the damage intentionally or by wilful and wanton misconduct;

(2) the damage arises out of use of the vehicle:

(A) by a person:

(i) who is not an authorized driver;

(ii) while under the influence of an intoxicant that impairs driving ability, including alcohol, an illegal drug, or a controlled substance; or

(iii) while engaged in commission of a crime other than a traffic infraction;

(B) to carry persons or property for hire;

(C) to push or tow anything;

(D) for driver's training;

(E) to engage in a speed contest; or

(F) outside the continental United States, unless the rental agreement specifically authorizes the use;

(3) the rental company entered into the rental transaction based on fraudulent information supplied by the renter; or

(4) the vehicle is stolen and the renter fails to:

(A) return the vehicle's ignition key to the rental company;

(B) file a report with law enforcement not later than 24 hours after the renter discovers the theft; and

(C) cooperate with the rental company and any law enforcement agency or other authority investigating the stolen vehicle in all matters relating to the investigation of the stolen vehicle.