Payback

I glanced over at the person next to me on the train the other day, a young man reading a book, and noticed a notecard with the following, somewhat cryptic, handwritten list (although aren't most lists, out of context, something of an enigma?):

Payback:
Equipment (gun)
Military operations
Send letter to Dickhead's wife

At first I thought maybe it was for some type of very violent video game (which also involves sending letters to people's wives...?).

Then I wondered if it was real. I'm not sure if I should have called the police or something...