One way would be to toy with the order in which the text appears on the page: that needn't be in the same order as the one for the text in the document. I.e.: the text on page could be "hello world" whereas if you copy it you get "old row hell".
The defenses of the person pentesting the court system have the same sort of energy, for theoretical example, hacking in-flight WiFi for the lulz and then claiming to have done the airline a favor by exposing their weaknesses for repair. Systems of authority tend to react poorly to pentests, whether authorized or unauthorized, and very poorly to the appearance of retconning the satisfaction of one’s desired outcome as altruistic intent.