In addition to Azkhaban Prison (as someone mentioned), the entire Harry Potter world, where children are given deadly weapons through which they focus super powers. There appears to be no police force of much consequence, or army. In fact it appears that the world's entire security force is dependent on one old man.
Not really. Mount Thomas had a population close to 8,000 or 9,000, so that's a modest number of police for a town of that size, not to mention whatever the surrounding population would have been. Statistically Australia has just over 2 police per 1,000 population, so Mount Thomas isn't too bad.
Wouldn't the alternative be worse? A world where super powered children cannot control those superpowers? There is a police force, the Aurors, though small in number are well trained and powerful. And who needs an army when you have a society of super powered people?
Then they shouldn't be calling Mount Thomas a small town. 8,000 is bigger than all but 5 of the largest population centres in Tasmania. I believe that the whole of the Forestier/Tasman Peninsula in Tasmania only has two policemen (at least that was the case back in 1996) .They have a population of around 2000, which rises to 8,000 during the tourist/holiday season.
Mount Thomas. Only reason I know that is that Shaun Micallef once set lyrics to the instrumental theme tune ("They live in Mount Thomas/Crime capital of Australiaaaaa").
Smallville, Kansas seems like a place to avoid. If you don't end up going crazy with some kryptonite induced super-power you end up being hurt by someone who has, or by Clark when he stops them. Add the meteor showers, tornadoes and freak accidents at the LutherCorp plant seems like a dangerous place to live. I personally wouldn't want to end up in the Harry Potter world either. Hogwarts seems like a dangerous place, between the Voldemort wars, dangerous international gatherings and dark wizards who can kill you as quick as sneezing and get away with it by saying they're 'impiriused'. It'd especially be dangerous for muggle-borns. I don't see how McGonagall in good conscience could invite muggle-borns to Hogwarts after Harry's first year. If I were her I'd tell them to flee the country right away and seek magical education elsewhere like France or United States or Australia. That and that those students never see any traditional education like reading, writing, maths after eleven years old. Sure their subjects use those, but there's no formal education specifically in those. You'd think the politicians need to know how to construct good arguments, the arithmancers how to write out and solve complicated math, etc. Anyway, I'd avoid Hogwarts and most definitely Azkaban as well. Diagon Alley might be cool before Voldemort's rise.
Because not all of the people with super powers are well intentioned and also because many of them are...children.