Libertine

It should be technically possible, though it would require some work.

Embed a unique user-specific (visual?) code in all video downloads, which does not restrict playback in any way, but does identify the user. I'm not talking about meta-information here, which could easily be stripped out, but something actually integrated into the content. Make it exceedingly tedious to remove, but entirely non-intrusive for playback.

Coupled with credit card data and IP logs, it could provide specific targets for lawsuits. Moreover, with some of the tube sites where the owners are actually doing the uploads, it could very well help in proving that.

It has some downsides, of course. Password-sharing and cracking would implicate the wrong people, there'd still be ways to remove it, etc. Still, it could be a decent start.

(just thinking out loud here - nothing serious, zero research behind this)

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