Forum Moderators: skibum
Take this with a grain of salt, but I think those that are really raking in the affiliate dollars should be the ones concered, rather than the new guys to the game. For someone who makes thousands of dollars a month doing this, a problem like this could mean some serious money lost. For us little guys, worrying about losing a buck or two, here and there, is probably not worth the time of implementing some confusing systems in order to resolve it.
This is just my opinion of course.
From what I've read, this is generally less of a problem than it used to be, though it varies with the program. It's the larger ones that get targeted. It also varies depending on how aggressively the merchant goes after the slime. Amazon seems pretty clean, for example.
It's a growing problem, hence a lot of people use a mixture of affiliate links and Adsense (with Adsense you always get paid, fair & square), giving one or the other prominence on pages depending on whether or not there are any "clean" merchants to be found in the particular niche.