I don't know about others, but my helmet is on my head when I get on the bike...it's the gloves that aren't on yet.Right about the cold tires. Scrubbing cold tires to warm them up after riding off whenever after start up one does so is a safety must; but riding off on start up without idling the engine first warms up cold oil faster and provides better lube than if one lets the engine idle for any length of time after a cold start. Heinz had a reason for writing the words "start up and ride off" in the boxer's rider's manual. I can't think of a good reason to disregard the instruction on most days. All that said, I would think that taking the short time needed to put on gloves and helmet before riding off is within the spirit of Heinz' instruction.
I am curious to know- where do you guys have your helmets when you are mounting your bikes if not on your heads?