I do not follow MON but my first guess would be that they keep track of the average yield per acre and if it is higher than expected (you don't see the adequate yield loss due to non BT acreage), then farmers were cheating (did not use the required refuge percentage).
Register for free to join our community of investors and share your ideas. You will also get access to streaming quotes, interactive charts, trades, portfolio, live options flow and more tools.