The existence of a method for one to change their appearance in anyone else is scary. But, that was not enough, so this recipe is easily obtainable by children ages as low as 12. Granted, the recipe is in the restricted section of the Hogwarts library, but we already know how that stopped Hermione.
Children playing Quidditch
The lack of safety and the danger of quidditch is apparent enough to anyone, even a child. In the Wizarding World, in every school for witchcraft and wizardry presumably, this is a school activity. Not just that, children, even first years (11-year-olds) participate in highly competitive quidditch matches.
There’s a ghost of a teenage girl in the bathroom watching living teens in there
A girl tragically died on the school grounds a few decades before Harry Potter came to Hogwarts. She died as a direct consequence of the lack of safety in the school. The thing that killed her has been planted there by one of the school founders.
The ghost of that girl is haunting the bathroom where she died, which is otherwise available for regular use by the students. And, they use it, while the ghost (of a teen girl) is there.
The Sorcerer’s Stone finale
It takes little to no effort for three eleven-year-old students to reach a room where a giant three-headed hound is located. That room is in a school with teenage students. And, worst of all, it is put there by the professors and the headmaster of that school.
As if this was not true enough, they put more deadly traps just in case a child would survive the first one. And, the traps are there to safeguard an item of great interest to any dark wizard or criminal in the Wizarding World. They brought this item to be kept at a children’s school…brilliant.
Hogwarts Teachers are super negligent
Looking at all the dangers surrounding the teenage students of Hogwarts is bad enough to think that no sane parent would ever enroll their child there (magical ability or not). But, the way in which the teachers there are addressing, or better said not addressing the dangers is even worse.
For example, an underage student of 11 years had a broken wand, improperly mended with duct tape. This is a serious potential danger to the safety of that child and all the rest. Many of the professors were aware of that and only mildly pointed out that he should have it fixed.