Is to make it personal, but be nice about it. It’s awesome when companies behave like real people, and this message is a good example of how to do it. It might make a few people think twice about taking your product without paying and earn you a new fan or two – I grabbed this from the front page of reddit, which tells you this example has at the very least generated a nice piece of PR for USB Overdrive X. If you sue your fans into the ground they will turn on you, and they will win, or worse, they will walk away. But if you treat them like adults, you never know, they might surprise you.