If $RandomLawFirm can sue for free anyone who has ever made a forum post by deciding that any one post crosses a line they retroactively moved, that will be the end of the internet in 2012.
It happens here all the time. A key reason is when there is something about the original article that feels offensive. Paywalls, Olde School attempts at control, and 12 pages for a 2000 word article.
We know the DMCA is a wreck. You as a nice guy are promoting a deep PoliSci position as their main motivation.
Unfortunately, it only takes a team of about 5 people in the right places to swipe the precedent that is being generated here, lock it in tight, and then ride the implications all the way to power & money galore. Then when whoever you are proposing has a change of heart, the power players beat him to it with an apparatus that cannot be undone anymore. Think of the TSA adventures.
Think of it again. Any law firm anywhere in the US can sue any internet poster anywhere in the US. Every single lawsuit will ruin someone's year. And whoever was going to agree that it was all absurd will get buried in a trumped charge and ran out of power to help. Then the rest of the sharks will enjoy a nice dinner.