Presently smoking marijuana is a crime.
Other than that, it probably doesn't matter. The teacher, however, is a role model for her students, and she should be held to a higher standard of conduct than your garbageman. So they can look at porn, but shouldn't be posing on bangyourteacher.com.
Drinking is legal, but if the broad's an alcoholic and she's coming to work hung over or otherwise inappropriately, she should be out on the street the same day.
Having a cell phone is legal. Teachers should not be allowed to answer their cells while in class. To make sure that happens, they should be fired if they fail to turn their phone in to the office when they come in to work in the morning.
There's the occasional article in the news about a mutant teacher that gets a sex change and wants to resume teaching the class it left. No, the children don't need that kind of confusion in their lives. The thing should be transferred to a different class once it's mental illness is treated.