I remember back in the late 1970's. Gobbing on each other was showing off your bravado. I could never achieve great green gobs of spit like some of my friends.
What level of force would be considered "reasonable" under law for the average citizen to defend one's self against a spitting (or other threat of bodily fluids or secretions) attack? By extension, wouldn't "flicking a booger" at someone also be considered an assault on the same level? Would any judge in their right mind convict someone for assault if they beat up someone who spit on them?