I'm German so my view may not be the prevailing one in the US, but I see my role as including making sure that the kids get a proper education. This includes making sure they are doing their homework and are revising for tests.
The consequence of forgetting (or "forgetting" ;) ) to write down their homework assignments or their books is not a work-free afternoon, an inconsequential negative remark by their teacher or a slightly worse test score (I'd argue that at primary school age consequences have to follow directly; a delayed test score does not register).
The first time it happened, they got a friendly expansion of the expectations. The second time an expression of disappointment. There hasn't been a third time.
Like: My son loses his sun hat. I could make a point about personal responsibility and let him get sunburnt for a few weeks until he saves up his non-existent pocket money to pay for a replacement, or I could just ask if anyone has it and find out that Joe accidentally took it home and that Joe's mum is going to leave it on the fence post at drop-off.
Also that might not even be an very unpleasant experience for them. In my kid’s school the teacher has plenty of other things to deal with so their practice is generally to have kids do the missed work quickly in the classroom and move on. I’m not sure my child is going to learn much about responsibility that way.
Instead, I take the time to make sure my child is able to get their work done on time. But that costs me time. This is where the consequences and learning responsibility comes in. Because I value my time, and the ways I make my children compensate me for my time when they have been irresponsible is much more memorable what they’d experience being unprepared in school.
Also the parents delegate can relay useful info from the teacher's as the only one who has direct immediate (without taking an appointment) through that channel. State is maintaining an app/website where teachers can send messages to parents but while some do it correctly, other teachers ignore it completely.
It is also interesting when some parents find out they have an issue with a specific teacher. Like this year one of my daughter had one lazy one and parents expressed their concerns to the delegate and debated on a common message to send to school.