You can stop using only the rear brake. But if there is more in the way than a stop sign, that is where the risk of locking up the rear comes in.
The way the brakes are engineered, the only way to lock the fronts is to snap them shut. Once the load is transferred to the front, you can squeeze the handle as hard as you can. The front end will start to wag near locking up so you do get feedback as to when to let up. The rear brake does not have that. The only feedback you get there is when the rear wheel tries to overtake the front :-/
You are definitely right on the competent instructor. That is an absolute life saver.
The way the brakes are engineered, the only way to lock the fronts is to snap them shut. Once the load is transferred to the front, you can squeeze the handle as hard as you can. The front end will start to wag near locking up so you do get feedback as to when to let up. The rear brake does not have that. The only feedback you get there is when the rear wheel tries to overtake the front :-/
You are definitely right on the competent instructor. That is an absolute life saver.