PW, after a while the finger will feel natural outside of the trigger guard. Since the gun spends the most time in the hand while not being fired you'll eventually only feel natural when the finger is resting along side the frame. The brain will go into "fire" mode when the finger comes off its home position.
Dudemar, regarding the your driver analogy, I'd have to break it into 2 groups. Group 1 would be your DMV book example. In group one would be the basics like safety, learning to use the vehicle control controls, and rules of the road.
Group 2 would consist of anything that occurred outside of the rhelm of normal driving. By never taking any higher form of learning they put themselves at higher risk if something goes wrong. Maybe they've never had any time on an obstacle coarse or race track with a qualified instructor. Perhaps they've never practiced and emergency lane change, felt their car slide or even used their brakes anywhere near their full potential....most drivers haven't. In other words anything that occurs outside of the drivers normal range or envelope of knowledge could potentially throw them a serious loop.
When the driving analogy is transferred over to shooting, group 1 would be the basics starting with safe operation and shooter technique. Group 2 would be taking the training to a level outside of bulls eye shooting. Maybe that's "tactical" shooting for some, like those interested in CCW, but it could just be leaning the advanced bio mechanics and mental training necessary for High Power or Silhouette shooting.