Yes, the controller errored in not following procedure on the altitude
snitch alarm (it's there for more than just dinging us pilots for
busting an altitude), but interestingly we have no information about
why the other airplane did not question who else answered to his tail
number... And how did the other airplane get down if he didn't take the
controllers instructions?... In controlled airspace I try to be alert
to similar tail numbers...

And, don't be too worried about Uncle Sam getting sued, he's got your
money to pay it with...

denny