How do you change the label on the router that got installed 8 years ago and is working fine? Especially since the owner of the cabin in the woods that you just rented for the weekend is into ... renting cabins in the woods, not geekery.
> have these complicated passwords that seem like overkill. You're probably right that they're some sort of default.
It is the default. If you find their router you'll find that overkill password printed on a label on the bottom. More enlightened ISPs give you extra stickers with the same info that you can put on the fridge or somewhere like that.