[Sailor Steve]

Maybe he didn't say anything because he was in shock.

That aside, I can only see this as a bad thing. The relevant clause from the Fifth Amendment is simple: "nor shall be compelled in any criminal case to be a witness against himself". So this ruling seems to be saying "The Constitution says we can't make you say anything that might incriminate you, but we can assume your silence itself to be incriminating."

I did like the quote from dissenting justice Goodwin Liu: "The court today holds, against common sense expectations, that remaining silent after being placed under arrest is not enough to exercise one's right to remain silent."