Yeah and when they come to Sword and Sheild to train with steel we have to train that habit OUT of them. 
I have been hit in the head A Lot while larping, and I have hit others in the head, and every time it was totally unintentional and accidental, and I have had my glasses broken, and it pisses me off but I get over it they are only glasses after all.
Shit happens, we are playing at combat, you swing at, what was at first a safe target, with a safe speed/power, and suddenly that target moves or changes into something else and you dont have time to stop it, or dont know how, and there you go an accidental head shot.
but if you allow head shots that accidental trend goes away which means you can control your strike all the way through.
With all of your experience Alista you must agree that it is easier to control a blow from the start to the finish of your swing, than change it halfway through. I can do it but then i have been fighting with steel for close to ten years now, and posses a skill level that most LARPers dont.
but if i am allowed to target the head and my target drops back, looks up, or ducks into my strike, well that is quite frankly thier fault, and hopefully the black eye they recieve for thier trouble will teach them a valuable lesson, i.e; Dont use your head as a sheild, (Said with all due respect to Mike and Skirmish but this is a mind set that your rule does foster)
I can control my actions but not those of others, And I am fully on Dereks side, if we allow head shots helmets or head/face protectors are a must.