Are there known tells that could be used to determine which model the video came from?

(This sort of question, and the Grok sexual abuse, is why I'd like to see mandatory invisible watermarks on generated images/video)

I don't think so. There are tons of self hosted models for video (they are smaller and easier to run).

Most people serious about this stuff usually have their own pipelines.

Since you seem to be better informed, I'm also interested in what self hosted models for video you recommend for creating my own Lego movie clips now that Sora is no longer an option for a paid service. There's tons, right?

Look up Wan and Hunyan for starters.

These are open weight models, so you can fine tune them on Lego content… But presumably they already have enough training data since they were made by Chinese companies who don’t give a shit about Western IP rights.

I'm not sure, but you could be right. Sora is/was the top-of-the-line platform for video generation, and the Lego IP videos were polished. Makes sense to outsource when your own energy grid is being destroyed. Anyone with an account and VPN could utilize the platform.

I'd like to know what self hosted models they've been using, if any, and who provided them, trained on Lego IP.