i honestly believe the trap was never designed to jump, but was rather a comercial implication, the trap could be made not to jump in one of two ways. 1) reduce the power. this would not have been an option as the trap had to be of the break back (kill type) rather than the legg hold trap it was designed to replace. 2) increase the weight. again this would have made the cost of the trap comercially unviable. so the only other option would have been to add a tunnel to control it. im in total agrement ian as ive seen and caught hundreds of rats in fenns without tunnels in the correct places and