I'm not really up on GMOs and all the chemical studies behind it and everything, but I do know that a farmer from Saskatchewan I talked to a few weeks ago was saying that farmers could figure out right to the 0.001% that something was infected with GMO. They can do tests and figure that out.
Labelling would be the most important thing. They should just be able to label it. Then everybody could make their own decision on whether they buy it or eat it or not.