Block the merchant's headquarters and branch offices to prevent them from spying on your campaign. Find them in Google, or the BBB to find their physical street address. Then add their location to the blocking list in the WADS.
Some WADS let you block a small region, down the county or municipality. Others only block at the state or provincial level. Block the smallest area you can.
I had to learn this the hard way. More than once I've seen a merchant shut off an offer with 24 hours notice. Then a couple days later I see knockoffs of my ads and landing pages.
These despicable merchants have no intention of a long term relationship with the affiliate network. They are testing their sales pages and watching how the affiliates promote the offer.
Once the merchant has tracked which advertising converts the best, they pull the offer from the affiliate network and use the intel - paid for by the affiliates - in their own campaigns.
So it is a good idea to block their geographic locations from spying in the first place. Then use redirects on your links so they cannot tell where the clicks are coming from.
Michael, I'm really impressed by the way you take me behind the scenes, and show me, step by step, exactly how you've managed to build up your affiliate revenues. Once again, you've shown why you're one of the world's top marketers!
If you want to live a happy life, tie it to a goal, not to people or things.