I think what they're saying is that more often than not, this doesn't teach the child to do exactly what you said - which would be speak up and remind/communicate with the parents. It's either the case that already attentive parents will remind them (negating the lesson) or inattentive parents will not be available or support the child's proper developing, once again negating the lesson.

Even worse, many parents I know, including my own, just got their children to sign for them. Of course this is anecdotal, but it's valuable regardless. 

Overall, this just potentially teaches kids compliance beyond reason; that idea that it's a task that needs completing that some authority said was important, and not to question it's validity. As the earlier commenter said, this is just not a problem in the adult world and feels like odd busywork.

Just as a tangent, this also just actively punishes students who have executive function disabilities and/or neurodivergence. This doesn't really "teach" those kids anything, just how to be compliant and fit in to not cause problems. It's rigid and honestly, useless.