Punishing the child for something the parent didn't do is unacceptable.
Happens all the freakin' time. (And a big chunk of it is that the teacher sees it as "parent would have done X if kid had reminded them, so I'm letting the kid experience the consequence of reminding / not reminding." Except that I often search my kid's stuff without being reminded, and often forget to do stuff I've been reminded about, so even for good kids with good parents, it doesn't work like that.)
The kids with bad parents get the consequences of that every single day. They don't need the teacher piling more consequences on top.
