"It is considered bad form to engineer a route to a standard above it's natural difficulty. For example, 5.9 routes should feature climbing attainable for a typical 5.9 leader. Engineering a 5.9 with such meager pro that only a 5.12 climber would dare try it is vain and cowardly. Save the 5.12 run-out for 5.12 routes, where the clientele can handle the action. Scaring the novice is amateurish."