What is obvious is that "Adi Shamir" is a name of someone living in a country dominated by Islam, and further that person is known to work in cryptography, so he is obviously a terrorist trying to send secret orders to other terrorists. In any case, he's a PITA for the NSA and other good guys like that. What they should have done, is to give him a visa, and redirect his flight direct to Guantanamo for further interrogation.</sarcasm level=big>

A tad more seriously: it's because of all those scientists of all the ages, that they have this situation where mere peasants can travel all around the globe, and make bombs or pilot planes into buildings. In the good old time, if a peasant tried to escape, he was eaten by the wolfs in the hoods, or killed by the highwaymen, so they stayed put, and the most they could try to do was to bump the armor of the lord with their wooden forks.

So it seems only natural to try to restrict them like that (perhaps it's a little too late).