Security in the Harry Potter World
I recently picked up Harry Potter 6 on Blu-ray. While I've read all the books, I've generally not been much for the movies. (I prefer the pictures in my head.) However, there is a photographic beauty to these movies that is worth both the time and the money (especially when the box set of 1-5 was on 70% off recently)... so I'm watching them and remembering the stories.
As with most works of art, the easy path to drama is to create a security failure. It makes sense, after all. As a creator, you may have a need to push your characters at time, and the easy (lazy) ways to push a character are to create a situation for them to react to. Thus, viewing the worlds as if they are real is a bit unfair... but on the other hand, nitpicking is fun.
In the world of Harry Potter, there are several security situations. The world of magic has to be kept a secret from all the muggles, the evil people have to be kept out of Hogwarts, and what is kept in Gringotts must stay in Gringotts. In fact, we know that there is some sort of magical muggle spy network, as Dumbledore knows to investigate Tom Riddle prior to his acceptance into Hogwarts. Why this same network can't detect the attack upon Harry by the dementors in book/movie 5 is unclear. Clearly, they need to invest in redundancy for the system.
Similarly, Hogwarts seems to have a surprisingly difficult problem keeping students where they belong. It took until book/movie 6 before they put up a firewall around the school, and even then, attackers manage to encapsulate an attack within a legitimate source (Katie Bell) and also fail to Draco's VPN bypass (terminated by vanishing cabinet). It seems that magic should be able to do better.
In contrast, Voldemort clearly knows a lot about security. He makes backup copies of his soul, just in case something happens (like a backfiring killing curse). Granted, the restoration process leaves a bit to be desired. If he really cared about operational availability, he would have tested the process and avoided that whole 12 year delay issue. (And here I thought 24 hours to deliver backup tapes from the offsite repository was a long time.)
Similarly, given that it's been established that there is a thing called "a trace" that can detect when someone casts a spell. You'd think that they could use the same practice during quidditch matches to prevent the audience from interfering with the play... but they don't. As a result, there are all sorts of amusing and dramatically-appropriate hijinks.
Lastly, in an environment where a bunch of students are awash in teenage hormones AND are constantly playing with potions AND know that love potions exist, you'd think that there would be an emergency bezoar in each dormitory. But there's not.
It would be interesting to see what the world would be like if there were more audit-focused monitoring points, reactive responses points and preventative spells. However, just as in the real world, these sorts of technologies are tempered by the economics of the situation, in the fictional world, there is a trade-off with dramatic tension. Sure, there are a lot of things that Dumbledore could have done to increase the relative safety of his charges, but to do so would have drastically reduced the possibilities for dramatic tension.
This would have reduced the number of books from 7 to likely 1 or 2. In our universe, Dumbledore lives for six whole books. If he had been a more protective head of Hogwarts, Voldemort may have been defeated much more quickly and the series would have been reduced. So, like most people, Dumbledore made a self-interested decision that had ramifications outside of himself. He got to live longer and be in an incredibly popular series of books and as a result, many of his students were placed in some wonderfully dramatic jeopardy. That's something to consider, I suppose, when there are security decisions that you have to make.
