In general you put your name on documents you print. But true that if you are a reporter in some country you might want to print stuff anonymously. How easy it is to modify a printer firmware to scramble those dots?
What do you mean? I’m confident that 95%+ of the documents I print do not have my name, or the name of anyone who has ever been in my house, on them.
"Printing a letter" is something I doubt anyone is doing in any meaningful percentage that this makes sense. A person printing a single small book they didn't want to buy is printing more pages just that one time than they will ever print with their name on them in their whole life.
Oh btw, you've paid a "tax" to unknown entities for this too: https://en.wikipedia.org/wiki/Private_copying_levy