I've explicitly taught this concept in my English classes, actually.

A run on sentence, for example, is a fantastic tool for expressing overly excited rambling from a character.

It only works for that purpose if the rest of the writing isn't full of run on sentences.

You have to know the rules and follow them well in order to break them for effect. I told my kids that if they obviously broke a rule for effect in their writing, I wouldn't hold it against them, but it'd only work if they were otherwise near perfect with that rule.

I had one take me up on it! It was cool. She also wrote a postscript explaining what she did and why, which was hilarious, because it was pretty obvious. She'd used sentence fragments to show incredulity. It was great.