No injuries to speak of, but it was close on 2 occasions:

Story 1:
I’ve told this one before, but when I bought my first pin I knew absolutely nothing about them. I figured the legs came off because I could see the bolts but never knew the head folded down. At the bottom of my stairs I have a landing big enough for a machine upright and a dolly, a half wall that runs up the stairs and a 90 degree turn. We had to pick the machine up with the head still up and try to fit it over the half wall but under the ceiling. At one point I thought we were going to have to break the machine apart at the bottom of the stairs. Days later I figured out the head folded down and I felt like an idiot.

Story 2: This one could have been serious.
Picked up a new to me machine and had it standing straight up ready for assembly. The entire family was excited and my wife asked what she could do to help. My 3 and 5 year olds were looking at the machine waiting patiently. I told my wife she could cut the plastic wrap off of the machine and I’ll start getting the legs on. What a brain fart! She cut the plastic and the head folded down to the ground. It landed within inches of my 3 year old. From that day on I make my kids sit on the couch until the entire machine is put together. Also miraculously zero damage done to the machine.