Around here, all the running martingales are fitted so that there can be no "direct line from the elbow to the bit". The rings are set maybe only an inch or two too low, when the horse is standing at rest. I'm not sure they are "fitted" much at all, more like One Size Fits All.
Their horses DO figure out the release, but mine at least, never learned to accept the bit. She learned to go behind it. And when the martingale wasn't there, she enjoyed throwing her head around and being evasive of just about everything.
I certainly understand there are times when feel-good training is irrelevant-- safety first is my motto. I resort to the "harsher bit" -- a straight pelham with a curb chain.