Curtis rented a safe deposit box from Reliable Safe Deposit Company, in which he deposited valuable securities and $4,000 in cash. Later, after opening the box and discovering $1,000 missing, Curtis brought an action against Reliable. At the trial, the company showed that its customary procedure was as follows: that there were two keys for each box furnished to each renter; that if a key was lost, the lock was changed; that new keys were provided for each lock each time a box was rented; that there were two clerks in charge of the vault; and that one of the clerks was always present to open the box. Reliable Safe Deposit Company also proved that two keys were given to Curtis at the time he rented his box; that his box could not be opened without the use of one of the keys in his possession; and that the company had issued no other keys to Curtis’s box. Explain whether Reliable is obligated to pay Curtis for the missing $1,000.