AFAIK the gate was for put in place to meet Eurotrash requirements in particular. By saying anything above 2500RPM is for abnormal situations only, they met the noise targets. Obviously the difference in take-off performance wasn't big enough for them to worry about and it was easier to just make it standard across all Airvans. It's sometimes a drag when some of the more observant pax notice you position the lever in the emergency position and you feel the need to go through the rigmarole of explaining that its basically just a sticker. Sometimes you get the vibe that theyre thinking to themselves 'righto this pilot knows too much for his own good'.