If your site only uses cookies for operational reasons, such as enabling login or maintaining a basket, you don't need to inform the user.
So anytime you see a cookie-banner that indicates that the site is doing something additional with cookies. Like tracking for ad-networks. It's a yellow-flag.
Except every single website just has a banner anyways because it's easier to cover your back then get legal involved every time you tweak something. So it has no meaning at all, in any way, except it's very confusing to some users.
The 'cookie law' is actually subtle genius.
If your site only uses cookies for operational reasons, such as enabling login or maintaining a basket, you don't need to inform the user.
So anytime you see a cookie-banner that indicates that the site is doing something additional with cookies. Like tracking for ad-networks. It's a yellow-flag.