I thought that Hogwarts had all kinds of charms and spells to protect it against dark magic whack jobs like Crouch. Sirius Black did break into Hogwarts when he escaped from Azkaban. Then all the Defense Against the Dark Arts teachers manage to cause havoc INSIDE Hogwarts, like Quirrell who was nothing more than Voldemort's taxi service. Dumbledore didn't stumble to the fact that Voldemort/Quirrell was inside Hogwarts in Book 1. Not good.

What's worse is that Crouch took The Marauder's Map. I didn't read what happened to it after Crouch's cover was blown. He probably sent it to the Ministry and Percy is using it as a screensaver on his computer.