Bullgrit said:
And according to the movie, this is all acknowledged as very dangerous -- like what would have happened to the little girl under the lake if Harry had not rescued her? The French girl seemed very concerned that she would have been lost.
Good god! Do the books explain this extremely dangerous stuff better than the movies do? Do the books give any explanations that perhaps these "games" are not as dangerous as they seem in the movie(s)?
In the books wizards are considered full adults at 17 (they can choose a vocation, and they can test for the apparate (teleportation) license), thus the age restriction Dumbledore places on the TriWizard Tournament. Probably because he was afraid Harry would enter. The Tournament had been discontinued many years earlier because of the high death toll, but Dumbledore revived it as a way to reach out to the other schools.
In the book there is actually a poem that goes along with the second task, which strongly suggests that people who are not rescued will die, but Ron says that it's just to make sure you get back before the time limit is up. I thought there was a thing later where it was said that they actually were in danger but the book is so huge I can't find it by skimming.
Many times, things are actually even
more dangerous in the books. I'm pretty sure The Whomping Willow has killed or maimed people before. People who go into the forest die and not just from the hoardes of giant spiders in there.
Actually, Quiditch is
more dangerous in the books. I'm pretty sure they mention that a few people die in the game at the professional level every year and it's not uncommon for a student to buy it as well. They're doing complex aerial acrobatics at a hundred miles an hour with no helmet and no protection

Many of the games we see in the movies and books are much shorter than normal, generally because Harry is just that good a Seeker - the game ends when the Seeker catches the Golden Snitch. Some Quidditch matches have gone on for days in brutal tests of endurance.
Being a Wizard is dangerous business and they don't sugarcoat it for the kids. They start to hint at things in the last two books that - to my mind - mean that your years at Hogwarts are just a means of keeping you comparatively safe and hoping to train you to a minimum level of competancy so you're not a danger to yourself and others.