It used to be the case but the trend, anecdotally, is towards a more-rounded learning experience where grammar and punctuation are considered less important.
Why would deduction of points lead to understanding?
Wouldn't one ask why points were deducted?
Only if that one is interested is his/her success and doesn't hate the subject. Plus, a child can be too shy to ask for an explanation.
You think someone could possibly keep this up for 10+ years?