It's not as cut and dry as that. Google does try to determine if a hidden element is being used for wrong intentions but there are many valid uses of this. I've

It's not as cut and dry as that. Google does try to determine if a hidden element is being used for wrong intentions but there are many valid uses of this. I've seen them mention this many times. A number one, perfectly valid usage is for dropdown menus. Naturally you want them hidden until activated via hover. There's also many, many other ways of hiding elements. You can make the position of the element absolute and move it off the page from site. I think you could also make any overflow hidden and then make element 1px in width and height. There's also the infamous 'same foreground and background colours' trick. The list can and does continue. This isn't really considering JS which opens up even more avenues to hide content either. I think to truly have an idea of what's maliciously hidden, the fully rendered page would have to be analysed. I think there are instances where this is being done but this is edging towards theory and away from concrete facts.