Out of interest I have just tried (I have an account but I’ve never uploaded anything). You can edit video info but critically not change the video. I think you can safely assume that every video uploaded has a unique URL. The only thing that can be done which could be used maliciously is you can “remix” the video. In the words of Youtube:
Sometimes, instant gratification video is just the thing you need.
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Reading that though it looks as if it creates a seperate copy with a new unique URL.
I can’t be certain of course so hopefully somebody else will have a bit more Youtube experience