"Terrorist-proof" like those "bomb-proof" vehicles in which people get killed.

There's hardening of a potential target, but there's no absolute "proofing" of a material object from highly-motivated, capable persons.

Some of the technologies that could be used to harden a target can also be used as a window for even more critical and catastrophic strikes, strikes that would make even a 10-plane terrorist plot look like child's play.

And then besides the security issue, there's the safety issue. That is, this could give new meaning to a "mechanical" problem that results in bad outcomes too, independent of terrorists.