I'm going to Berlin for two weeks in May, and I ordered online some symphony and opera tickets. You are supposed to print them yourself at home, on a laser printer, which I did.
Perhaps I'm a little paranoid, but, I noticed that the tickets say "ticket only valid when printed on white, standard size (DIN A4) paper."
Since I'm in the United States, I don't have any DIN A4 paper -- which is a European paper size just slightly smaller than the letter size paper that is standard in the USA.
Is this going to be a problem, that the paper I used was not the exact size required?