okok, I meant to reply earlier, then work stuffs got into my way, the next time I notice it, it is 8 hrs later...
I agree with you, p13.
I think it also depends on other variables. For instance, if you have a much higher lesson practice ratio (let's say 4 hrs of practice per 1 hr lesson), you might as well just practice it - even if you are making mistakes (i.e. not perfect), your coach would easily notice them before becoming muscle memories. So in that case, one could "just do it."
To think about it, I guess I'll put myself in "just do it" camp - or so I hope. My take is that - if you don't do anything, you get nowhere. If you do something, you at least would get somewhere, even if you are going on the wrong direction. And even doing bad things might not be a bad thing - some people learn through negative experience, and sometimes, the "wrong way" might be a necessary evil. Even if the "wrong way" would damage your body, assuming that you would take another lesson soon, these damage should be minimal.
Also, it is more realistic. You don't stop at the middle of a competition/social dance just because you make some mistakes. By practicing "just do it," you would hardwire your brain to push your body through difficulties.
From my personal experience, I used to dance at the ratio of 1:20~40 (lesson:practice), and just about everything is reversible.
I just remember a few things - my last partner used to be really mad at me, since I would dance maybe a few bars and stop (because something went wrong).
, ok, maybe I am not really in "just do it" camp, after all.