Red (Incidentally I have recently started to do cryptic crosswords and I nearly fell off my chair when I worked out your nom-de-plume!) To return to the Cortez example---the Incas + others didn't do too well after they were stopped from carving hearts out of living human sacrifices, so maybe there is something in it. On the plus side the New Guinea tribe which ate their catives' brains no longer get the prion disease, Kure, so banning cannibalism has had a good outcome.