an engineer designed an outdoor elevated patio that was expected to accommodate a conference meeting 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 rock concert, and sold 400 tickets. in fact, over 400 people attended and packed the patio. the enthusiastic crowd began jumping to the music and caused the patio to collapse, injuring many of the 400 paid ticket holders. how would liability be determined in this case?