The way NASA does passing in HPDE3 makes sense if you understand the progressive nature of their HPDE groups. As you progress through the groups, they're trying to get you more and more into a "full racing" environment.

To be approved for HPDE3, you have to not only demonstrate good basic car control and course reading skills, but also situational awareness. In theory, every driver on the track in a Group 3 shared_session is well aware of the traffic around them and they "know the score". The courtesy and safety are still there, it is just "unspoken", if you will.

You're coming up on turn 16 and you've watched the guy behind you reel you in for the past 3 turns and you just know he's going to make his move in the next straight (because that's what YOU would do if you were him). As the driver being passed, you don't have to DO anything other than keep driving your lap and be predictable. (which is why they teach you to stay on line... that's predictable) The passing driver has the responsibility to make his pass safely.

Nothing wrong with a point if you know you're being passed and can safely offer a point of reassurance. But, once you get into HPDE4 (or actual W2W racing), you'll find that offering up a point-by mid-turn is kinda hard to do!

So, yeah, for the less-experienced groups, point-bys are definitely the safe way to go. That communication is required at that level of driver experience. As the inexperienced drivers (or those who simply can't master "situational awareness") are weeded out at the higher levels, you'll find that communication simply gives way to awareness.