Probably the most "authentic" hit I ever took was at a 150th Kennesaw Mountain event. We (federals) were storming some works. I thought I'd be clever and go around a corner with a small squad and came face to face with an unseen cannon about 10 yards in front of me which proceeded to knock me and the few others literally off our feet. The gunners were horrified they killed us... until they saw us lying on the ground laughing.
I guess if it was real we would have been pink mist, though.
Although I do understand where you're coming from, I f everyone had this attitude, events would be very short and not very entertaining for even the participants….
My knowledge of reenactments only extends as far as the film Gettysburg, because I know reenactors were used extensively in the battle scenes. And every time I watch it I think that I would not like playing one of the dead soldiers, because I'd be petrified of being stepped on. I don't know if that's a big concern. But it would be to me.
Usually we try to be careful to not step on dead soldiers. I remember a tour guide talking about how a soldier stepped on his comrade's stomach during Pickett's Charge.