These people reserve the right to read through your stuff then reject it if they think it "unethical".

This happened to us after we’d arranged a print job. It was a poster for a lecture on the 30th anniversary of the Falklands War, by the doctor of an Army unit who'd saved over 600 lives - mostly Argentine. We're a scientific research foundation dedicated to solving the psychological and neurological problems caused by wars and disasters.

Greenprint staff told us they wouldn't print the posters as they didn't think doctors should join the Army.