Anyone who is thinking about leaking anything classified only needs to spend thirty seconds typing "Snowden" into Google to find out what happens when the federal government identifies the leaker. They then decide if it's worth the risk and how much time they will spend on covering their tracks. In this case (if true) it sounds like Reality Winner decided that they simply couldn't cover up their leaking and threw in the towel.
Much has been made of the watermarks on laser printers, we've known about those for a long time. Not everyone is aware but it's the sort of thing you can find out about if you put in time to do the research. After doing my own research, it doesn't seem like these watermarks really came into play; the NSA simply looked up everyone who had accessed the document and inspected their workstations for clues.
