In BA everyone seems to follow the rules which proves that floorcraft can be emphasized enough that people learn it. And you're right in that there are consequences for not following them. Perhaps where you are in CA, the milongas would be empty if rules were enforced, but that's not true everywhere. The people here who grossly violate any kind of floorcraft are doing moves they got taught in the classes they took. If they had been taught differently, they would probably dance differently. And there are no consequenses for what they do, not even a shortage of partners since there are so many followers and so few leaders, so there's no incentive for them to change.
Interestingly, when my partner first went to BA, he said he took some lessons there (had had very little Arg Tango prior) and got shown all the "tango-for-export" steps. When he went to a milonga, he had no idea how to adapt (but at least he recognized that he needed to!) or how to dance in them. Many of the tango teachers even in BA teach fancy stuff and no social dance skills.. at least to tourists.
Then he got some instruction from the older milongueros (met Tete' and some others) did alot of observing, and also applied floorcraft he knew from ballroom and had more success on subsequent trips. It was during the time period that Daniel Trenner was beginning to really explore the purely social tango techniques touring with Rebecca Shulman and he took from them too when he got back to the states.
It seems even in BA, you have to really search for instruction in traditional social dancing.
