If it was a total pressure (pitot) tube that was blocked, then I don't see how the crew would see an airspeed mismatch problem until about 30 or 40 knots on takeoff, since that's ram air pressure he blocked. Maybe I'm missing something here from the flawed and spotty reporting. ??
I guess somebody crazy is bound to do this once in a while. This guy accessed the aircraft on the tarmac, unusual at the time since the plane had no outstanding problem reports to fix.
Also, why did it take so long to arrest this dude? Sabotage happend in July, and he was arrested in Sept. I think they found and fixed the problem and knew the foam didn't just magically appear there.