[accountface]

I agree with you — BUT, I have conducted a fair amount of user tests where someone will not scroll. It's often an older demographic, but I've seen 30 year olds fall into it as well.

So it's not always a designer saying "I know better than you."

I do think that they're going about solving the problem the wrong way though. Your design should on its own encourage scrolling by making it obvious that additional content exists (avoiding so-called "false floors") — it can be harder to do this than unchanging your design and suggesting scrolljacking, which is why I think we see it so often.

[afandian]

I think that's a different issue. If people don't know they need to scroll (your false floor example), that's a failing of the visual language, so it's entirely appropriate to put an explicit message "you can scroll" to make up for the failure of visual language.

I'm talking about what happens when you actually do scroll. In my experience those seem to the same sites that are visually confusing are the ones that re-program your scroll down as a page-down...