>I am not even mentioning that every criminal can infiltrate Hogwarts and do what he wants with the transformation potion.
Also an enraged God of that realm could appear and destroy the whole city because he stumbled upon rock that morning. It's a book and books have their limits on what is possible to occur and what's not, you are going out of that boundary, expecting every corner case that came up to your mind be mentioned in the book. Just assume that such a thing cannot happen.
>It is just that the system with all that tournament participant selection is extremely flawed and yet they ignore the flaws and just proceed further
It's normal behaviour in some situations. You don't strengthen something to perfection, 'cause it would require too much effort, instead you have covered the most dangerous or harmful case. Or at least you put things the way you have control only when you need to. Capiche ?
>Yet they let kid to participate.
Actually I would do the same thing be I that old gay magician person. It's in his nature to have a little bit of fun, tho I'm sure that these kids are put in less danger as the main target is Harry. There is nothing other teachers wouldn't be able to handle. The most dangerous part will be handled by me or by others involved in the matter deeply, like by that simp Snape.
It looks like you don't dig into characters deeply, expecting perfect crimes, but they actually look more realistic that way.