In my 40+ years of hunting the same piece of property that I do I guess I'm close to, if not at already at, killing 500 deer in my life. Keep in mind I'm not a slob htunter but we had a number of years where we had to do some serious population control after all the soybeans went away in the mid 80s and into the 90s I guess. Anyways, in all that time, I can not remember head shooting a deer either intentionally, or accidentally. I suppose if I was on a meat hunt and a doe was close by and the only thing exposed was her head, I would do it. Now if it is a doe or a very mature buck without a nice rack and I want to ruin as little meat as possible then I shoot them in the neck close to where it runs into the head. That way it is hard not to miss the spine and you still get most of the neck meat. I've done that a few times.
It reminds of a funny story. Bojie Beers' hunting camp, Alabama River Hunting Lodge, is just up the river from us and we go up and visit them every now and then as we are all friends. One evening years ago they brought in a doe with its head pretty much blown off. Apparently, the hunter had killed several does like that on his trip. The guide, the famous (or infamous Walter Traylor), asked him why he kept shooting them in the head like that. The hunter told him because he wanted to follow all the F&G laws. Walter says "What?" to the guy and after a bit more questioning it comes out that this newish and gullible hunter was told by his buddies that in Alabama we have a very liberal doe allowance but in order to be legal you have to shoot them in the head. The guy believed them and was following what he thought was the law. I guess his buddies went to bed every night laughing themselves to sleep.