Yes, there is that risk with anything you do (including your own website and your own email list), but surely by now they have heard enough people complain online that it is very unwise to build a tall building on a shaky foundation.
Aside: why don't they use competitors such as Vimeo and post the videos on Vimeo [1] first, and then post those same videos on YouTube after two weeks? If their audience is really that engaged, shouldn't they be following them to Vimeo also? It would be a two in one deal - the creators create competition between two online video services (which is usually good for them), and if more creators move away from YouTube the consumer also benefits from greater choice and is more likely to go check out Vimeo, leading to a possible virtuous cycle. A third and unexpected side benefit - less data collection about your online practices by an internet behemoth.
[1] From what I can see, Vimeo also has options to monetize your videos. https://vimeo.com/blog/post/learn-how-vimeo-on-demand-helps-...