You are definitely right, and while we've thought through several threat models blackhat marketers are endlessly creative. Might make for a good blog post depending on what we learn
There are some that have made amazing use of Mechanical Turk without actually getting caught - that is one vector I think the affiliate industry has greatly overlooked.
I guess it could work if you abstracted it enough so that it's not apparent to the worker, but it wouldn't be trivial to execute. Using VAs on Odesk might work better.