...or just use steganography. Steganography in videos can be made to be invisible to the naked eye, and extremely robust - even to video compression. It's also difficult to detect, and even more difficult to remove/tamper with. What the author of the article is proposing is actually a kind of steganography, albeit a rather crude one, and probably rather difficult to implement (since scene timings will be different fo…
This might be a very naive suggestion (I know nothing about the subject) but couldn't you just take two copies, XOR them and blank out the difference to defeat such signatures?
You can if you have the original file, but then what's the point?
Otherwise, take image a=original+f1, image b=original+f2. Then if you e.g. average them you still have c=original+f1/2+f2/2 -- so both signatures are kept (theoretically if either you have a large number of sources you could average the signals out of existence, or perhaps the system isn't robust and can't detect multiple sigs). This assumes the introduced signatures are indistinguishable from the source (quite reasonable).