Using router password recovery features is mildly annoying, because it wipes out the configuration for security reasons and you have to rebuild it. That's fine as long as you've got either a backup or decent network configuration documentation - if you don't, then you're hosed. If the city's network administrators don't have good documentation, or it's all in one place where one person can trash it, they've got serious management troubles, beyond whatever damage this guy may have done.