It would be fairly trivial to encode information in single frame swaps (both audio and video) in such a way that these swaps are imperceptible and irreversible.

It would be fairly trivial to encode information in single frame swaps (both audio and video) in such a way that these swaps are imperceptible and irreversible. There are many compression artifacts that could be used similarly (e.g. does a 1 bit increase in average screen color is rarely going to be perceptible). Regarding hi/low pass, theoretically this should be fairly simple to defeat by spreading the information across multiple frames. Note: I know next to nothing about watermarking, my comment is just a purely hypothetical attack on your trivial assumption. The trivial work around has trivial work around work around... ;) <insert that scene from the big hit>