I actually mentioned potential copyright lawsuits in a comment to a friend a week ago. Its a very serious and real issue which it seems from your post is about to come to a head. I personally think the costs themselves would be enough to put Steemit out of business, the lawyers would be putting in overtime to sort out the legal intricacies for years as it would to the best of my knowledge be test case without precedent, and how do you delete the undeletable ?
More than ever, there needs to be guardians and an auto system for running all material posted here through a tineye type of check for pics and one of the many anti-plagiarism scanners for text or it could simply be the end.
I see the scammers getting clever now by putting their names on pics and removing all meta data off pics which are obviously ripped off to try and fool the checks.
Simply a case of needing more personal and all the tech available to sort this now.