That bit about guys who boresight their rifle and then go hunting is not only scary, it is so true! My father-in-law is an anasthesiaologist (I'm *not* a doctor, so I probably misspelled this) and the hospital where he works often pays for a deer lease for the doctors and their guests to hunt. I've seen some these guys do all of the following:
1. Use what ever ammo someone else has when you run out---no need to resight.
2. If you miss a deer, set up milk jug 100 feet away when you get back to camp and if you can hit it, it's not the gun.
3. Borrow a spare rifle from a friend and never fire it becuase "it oughtta be sighted in."
It's not because they are doctors that they do these things, it's probably because most of them only hunt because the hospital provides a free opportunity.