Absolutely right Matt. The body is aware that if something is in the way, it will adjust dispite our best intentions. Here's a dumb example; put your left hand palm facing your nose, right next to your nostril, now with the other hand, try and clap your left as hard as you can. You don't have to try this to know you will automatically move your left hand or head to avoid a bloody nose.

If your right hand stayed on plane and you didn't move, there would be a painful collision and your wife would call the men in little white coats to take you away to the funny farm...where life is beautiful all the time...
In terms of coming down on plane, it's a requirement that the right hip moves (clears) to make room for the right side of the triangle to bring the clubshaft down on plane. Hence, "axis tilt", "hip slide", "Hip bump", and all of the other terms used to describe the downstroke transition move. If the hip doesn't clear, then the right side has no alternative than to "go around" the house, resulting in a bent plane line. Fore Right...Fore Left...
Bagger