I'm thinking about spending some time this weekend doing automated analysis of NTSC and PAL GOUT. I want to make sure we've found all of the unintentionally-interlaced frames and that the two are truly in sync after making the changes you suggest, Chewtobacca.
I plan on using FFmpeg's idet filter for checking the former. The latter can be checked by diffing files containing the begin-shot-change numbers from each source.