Since we have US citizens involved with al Qaeda (Buffalo cell, Portland cell) and those people have travelled to AFGHANISTAN, I don't see any way you could avoid NOT asking for this information if you are trying to keep track of people like that. I agree that it is something we have never had to do before, but I don't understand another way to track people who leave the country for nefarious purposes. We don't have enough FBI agents to tail everyone who is suspicious, and this method would flag suspicious people through a computer data base as they leave the country.
If someone has a better idea I am willing to entertain it.
I'd choose freedom and accept the slightly greater risk. This is one of the few times I would be willing to pay for more resources to govenment to focus on the target and leave the rest of us alone. Afterall, the two most important functions of the government are defence of the citizen, and defence of the citizen's rights. Compromise one, and they have failed at both.
This is a very slippery slope.
People who leave the the country for "nefarious purposes" are not going to self-report their movements. A committed terrorist is simply going to bribe their way around visa stamps, or tear out relevant pages, or simply "lose" their passport proir to return to the USA (just stopping at the local embassy to get a temporary replacement passport for $55). Then they'll lie about their travels.
So in practice this "rule" will not help law enforcement one iota.
For example, travel throughout the EU (where a huge number of terrorist cells are located) requires no visa whatsoever, and there is nothing placed in your passport to indicate your travels within EU countries.You can run from Spain to Sweden without a single stamp.
So again, terrorists and criminals will simply lie about their travels. Only the sheeple will be forced to self-report to the USG regarding their private and personal activities.
This is a huge warning sign that we are heading the way of Soviet-style travel restrictions.