I've just had quite unpleasant experience with this question:
First there was a guy who plainly copied/pasted my answer and got 2 instant up-votes. I warned him that I had flagged his answer, after what he deleted it and then down-voted a bunch of my own questions/answers, including that one. Here is his deleted answer, which can be seen if you have >= 10K reps.
Now there's another bloke with a canned link and 2 up-votes.
What's the right way to deal with such activity?