Dan, your first response seems self-contradictory (to me, anyway); if I'm reading it right, I'm going to disagree.

Originally posted by Dan Collins:

if two players are taking actions or shortcutting in a way that all players understand what is going on, then we don't need to…{get involved}

seems to contradict

Originally posted by Dan Collins:

we may want to ask AP whether he was placing all the activations on the stack simultaneously

Why would we ask anything, if the players are OK with what just happened? No rules were broken, we didn't see an infraction - we don't intervene.

A bit of clarification on the English that Brian used, and I agreed with…
Supplanting the rules would mean replacing or overriding the rules - the shortcuts do NOT replace the rules.
Supplement the rules means adding to, or enhancing, the rules - the shortcuts DO add to the rules.

Most of all, the shortcuts give us an invaluable set of tools to resolve many common disagreements about where we are in a game. In the example where both players accept where they are, we don't need to intervene.

d:^D