An engineer designed an outdoor elevated patio that was expected to accommodate luncheons of up to 100 persons.The engineer considered the load-bearing structure on the basis of the weight of 200 persons as a safety factor.

When the structure was completed, the owner decided to use the patio for a local charity concert, and sold 400 tickets.In actual fact over 400 patrons attended, and packed the patio for a "standing room only" concert.The enthusiastic crowd at one point began jumping to the music, and the additional load pressure caused the structure to collapse, injuring many of the patrons.

How would liability be determined in this case?