Those are stickers on SteelBooks these days
No telling w/ amarays & DigiBooks though
Lots of times they'll print reversible art in DE so that you can open them & flip the paper insert in the amarays
They often label these w/ the term "wendecover" in Germany
...so if you see that (or its a new SteelBook) then you should be ok

I believe it's a law in Germany & the UK (perhaps other countries in EU, too) that all media must have a ratings logo on it that can be plainly seen, at least while it's still sealed
Hope that helps
-Rod