There are well-documented solutions to this that don't rely on the PSL. Choosing to ignore all of that advice while hosting user content is a very irresponsible choice, at best.

So the problem here is that Alice on alice.statichost.page might set a cookie for the `.statichost.page` domain if she's careless (which is sometimes the case with Alice). This cookie can then be read by Mallory on mallory.statichost.eu. Or the other way around, if Mallory wants to try to trick Alice into reading his cookie. How this can be prevented without the PSL is something I'm very interested to hear more about.