Some parchment is blank because - and this is key - nobody has written on it yet. Very hard to read. Very tricky.
And yeah: you can turn any parchment into a blank scroll with the right tools. If it's a piece of evidence you need for something, you'll be annoyed later, but you can still do it.
Kind of odd that you can make paper while everybody else in the world seems to use parchment only, but there you go. Source Hunters are magical. (But are not fisking Ponies, and I really hope we don't get those mods infesting this game like they did with Skyrim.)
