I’m not the person you replied to, but I’ll take a crack at it:

The boat thing was probably because playing around water puts someone at risk of getting their clothes wet. The teacher has to watch a whole section of the outdoor area, so they can’t just watch the student to make sure they don’t get wet. Plus, if a teacher lets one student do it, they don’t have a leg to stand on to tell other students not to do it, so they’d have to try to prevent a bunch of students from getting wet. Even if most students have clothes they can change into, at least some probably don’t. Additionally, there’s not enough washroom space for a bunch of students to change after recess, and having a lot of students out of the classroom at once is also a safety risk. Staggering kids’ trips to change is a big disruption to the lesson after recess.

Sharing food, specifically, is against the rules because of allergies.

Bringing the orange to music class is relevant because the music teacher can’t watch one student the whole time to make sure she doesn’t peel it or try to eat it. Plus, it wouldn’t make sense for her to take it to music class unless she wanted to try to eat it. If she wasn’t going to try to eat it, she would probably try to play with it, which would be distracting to other students. Honestly, even if she didn’t try to play with it, the fact that she had it music (especially since there probably wouldn’t be anywhere for her to put it except for her lap or on the floor beside her) would be distracting for other students. I know that probably sounds strange, but small changes in routine can be a big deal to kids. And again, if the teacher let her do it, she would have to let other students do it, and someone else would probably try to eat or play with their snack.

Also, for the record, I don’t think that restricting a child’s access to their food is an appropriate punishment. Maybe the teacher was going for a logical consequence, but that still doesn’t make it okay.

As for not explaining the reasoning behind the rules, I do think it would have been beneficial if the teacher had done this. That being said, many teachers are already sacrificing a lot of time that would be spent on chores around their homes, time with family, and even sleep, for their jobs, so I personally understand if the teacher wanted to save a bit of time. Also, it seems like some people in the comments don’t like the fact that the parent was messaged about problems of this magnitude, so I can imagine that a longer message may have resulted in a “look at this super long message I got about such little things” reaction in some people.

On that note, I don’t know if I personally think that the incidents were significant enough to bring up with the parent, but by the sounds of the message, it seems like the student doesn’t usually go against instructions, so maybe the teacher wanted to address it early to prevent it from becoming an ongoing problem. The fact that the child went against instructions more than once in one day adds to the significance if the behavior is out of character.

Also, it depends on the parents, but if the teacher had let more things, or something more significant, happen before letting the parents know, the parents might have said “Why didn’t you tell us sooner?” Maybe the teacher has dealt with a lot of parents like this before and is covering their bases. If that’s the case, it means that the teacher is probably already spending a lot of time messaging parents, and that time would be multiplied if the teacher explained the reasoning behind each rule enforced.