The designation of the aircraft, C-150, may tell the story here. That's old. Very old. The new Cessna equivalent is C-152 and has been for a very long time.
I suspect this aircraft had minimum instrumentation. Certainly not GPS or anything capable of giving a preprogrammed warning of the restricted area. These guys were relying on maps and looking for landmarks in an unfamiliar area.
Their mistake was in underestimating the difficulty identifying landmarks in a huge metropolitan area. That was a mistake made before leaving the ground and it's not a big one. It's a small one that became big through mostly bad luck. Recognize that they could have drifted off course 10's of miles in any other direction and we would never have heard of them. It's an odd truth of low altitude flying that the less developed the area, the easier it is to visually navigate.
The old guy should have his ticket pulled and he'll probably agree. The young guy is a student and by regulation pretty much none of this is his fault. He will have gained better experience from this than any other student at 30 hrs.
Yeah, the PIC is going to take the hit for this one. How could he let the aircraft get into Bravo airspace without contacting ATC, never mind getting into the ADIZ (which he may not be too familiar with). THe PIC instructor failed to show the student how to track his progress against expected landmarks, which is the main point of such a trip.