How would be able to get past stochastic transformations? "frame is slightly wider than average of other pages == push 1 into FEC" could be stymied by making pages randomly wider or narrower, so now the average is different and the frame you are expecting to be slightly wider may even be slightly narrower than the average now, garbling your encoding.
Sure, but you're taking two things for granted: you know this is the approach used, and it's the only approach used. If we assume those, you can work around any watermark.
