A locked vehicle warranty requires that for any insured property being carried in a vehicle, reasonable measures be taken to securely close the vehicle such as closing and locking doors and windows. If any loss occurs to such items as a result of theft, there must be visible signs of forced entry, such as a broken window or scratches inside of the locking mechanism.   If you are not able to prove that there was forceable entry to the vehicle, the insurance company can deny the claim.