Definitely. In my experience, it gets a lot worse when you start re-assigning variables ("But x = 3, you can't say it equals 5"), and worse again when you have

Definitely. In my experience, it gets a lot worse when you start re-assigning variables ("But x = 3, you can't say it equals 5"), and worse again when you have to start using == and = concurrently. And then weak typing vs. strong typing vs. what the student expects, but at least that's easy to head off at the pass if you're anticpating it.