I worked on a draft for a similar idea for NSFW (Not Safe For Work) posts.
Discussion
It used the Yahoo! NSFW model but significantly increased the downloadable size of nostr:npub18m76awca3y37hkvuneavuw6pjj4525fw90necxmadrvjg0sdy6qsngq955 and was difficult to get to work with the Kingfisher (for images/GIFs) stuff that was used at the time. Might be a similar way to do it with built-in AI in the device though.