What concerns me and other FReepers is the overt fraternizing of the SCOTUS justices with Obama, given the several cases challenging his constitutional eligibility to be president that SCOTUS has already considered and the other cases likely coming its way.
Judges shouldn't be socializing with people who are parties or attorneys in cases coming before them; to do otherwise violates the canons of judicial ethics.
I don't think you would be to happy if, for example, you were suing someone and you spotted your opponent hobnobbing privately with the judge(s) assigned to the case. An honest, ethical judge should never even create the slightest suspicion that he is partial to one side in a case before him or which will likely come before him.
The concern grows daily, especially with this type of ruling.
You may remember from a couple of years ago when the Supreme Court denied the motion to disqualify Justice Scalia from hearing a case against Vice President Cheney, even though Scalia and Cheney went hunting together. Scalia said that they didn't talk about the case during the hunting trip, and that was enough. So the same precedent seems to apply here.