When I was in public school. If you were caught using your left hand to write with. You got the ruler over your knuckles. Back then it was considered wrong to write with your left hand.
My mom went to public school, and she witnessed a few instances of what you describe growing up. When she discovered I was a lefty, she went to the school I would be attending and told the kindergarten teacher and principal, "My daughter is a natural lefty and I don't want her corrected. It'll frustrate her."