...and then sit in the conga line prior to takeoff with the mixture full rich and the plugs fouling?
I just had a breakfast flight to an airport with a field elevation in excess of 6,000' this morning. If my factory checklist said mixture rich, should I comply or violate another old wive's tale or a lawyer driven POH recommendation?
For the OP, probably not.
Good points! as the OP didn't have a location I assumed he was in the centre of the universe aka the United Kingdom