Haven't had time to catch up on this thread until now (too busy crushing creativity...).
Yetanother I think your education did fail you if you weren't actually taught about colons and semi-colons, yes. I must point out that we are absolutely compelled to teach these things (and I definitely agree that we should). The problem is that many pupils (and I really mean many) will not get it unless you dedicate a quite unreasonable amount of time to it. So, you do teach it. Some will master it; with others the regular reminders (in the form, preferably, of talking to them about their work, not covering their work in red) will start to work; with others, they simply won't ever really get it. In some cases that will be through laziness, but certainly not all. And they will lose those marks when it comes to exams. That's how it works.
Obviously that is a simplified version of what happens. Obviously teachers try various methods. We attend many training sessions and experiment with different approaches. We do not rely on random irate posters like counterpoint to throw TED talks at us online. The childish insistence on putting 'teachers' in inverted commas is very rude, counterpoint. Who made you the expert?
I agree with the analogy of rules as a scaffold which provide a framework for creativity. The problem comes when it takes all the time (and more)to teach the framework, leaving no time for creativity. That cannot be right. At some point, you have to let the kids be creative with whatever level of expertise they have. And that means allowing some pieces of work to be riddled with (gasp) uncorrected errors so that the child can explore a new idea.
This thread started because a parent started a snidely titled thread to complain that a teacher was not covering her daughter's work in red (or green?) pen. Is it any wonder that a number of teachers have waded in to explain that this is not the only way to teach? It's the sheer arrogance of non-teachers telling teachers how to do their job that annoys many posters. It doesn't happen with other professions; teachers, it seems, are fair game. And so, as I've said before, children are taught contempt for teachers at home. This undermines teachers further, and schools become even harder to manage.