Two words: false positive. Anyone with any experience in data mining would tell you that a 60% success rate in selecting the desired targets would be astonishingly good. Much of the 40% failure rates will be false positives.

Anyone remember the lawyer in Seattle who came up as a false positive for the Madrid bombings and who had men in ninja suits stalking around _and inside_ his house for weeks as a result? Who was threated with being "rendered"?

sPh