Death does not bestow legitimacy. Why did they continue speeding into the checkpoint even after being warned? What exactly were they up to? What (or who) were they bringing in that would make it worth risking death to get it past the checkpoint? If they had been legit, logic says they would have stopped when warned. The fact that the woman was a communist working for communist causes doesn't help their case, either.
There are plenty of questions to be asked, but the Italian intelligence agents were not on a suicide mission even if their passenger was a Communist. This was not a staged event. I don't buy your conspiracy explanation. We need facts not speculation.
They must have stopped at other checkpoints along the way, which makes it curious as to why they didn't stop at the last one.