Yes, I'm with ron15. Someone out there is better at revenge than you, so threatening the cheat is not always risk-free.
I wish I had time to carry out such threats, for it sounds satisfying, but I too have settled for spending time on my own sites. Truth be told, I don't worry about my own ranking as much as I should. If it levels your playing field, then I'm in support.
I am collecting for a rainy day emails from link outsourcers (3 so far) in SE Asia who attach spreadsheets of their entire portfolio of link sites as evidence of their might. At best this gives me data to observe the performance of their clients in various industries.