Uhh… what do you think the notice is telling you…? That’s it’s not a legal copy. Now you can’t claim you didn’t know… this is literally a legally accepted measure to remove that entire defense that you didn’t know. It’s hilarious you comprehend that, but don’t see how this notifies you of it being illegal! It’s along the same veins of reselling a book without its cover and the notice telling you. Of course it’s legal and accepted to remove your ignorance defense. Ignorance has never been a defense and this would be no different.
And yeah people have been arrested for those before, of course I haven’t personally seen it. That doesn’t mean it doesn’t happen.