Mainly storing a link to this interesting paper that raises some questions:

William Press, "Strong profiling is not mathematically optimal for discovering rare malfeasors".  Weak profiling apparently is---under the assumptions of his model, which seem to me a rather imperfect fit, but not wholly irrelevant, to most real-world terrorist-screening scenarios.   No implied view from me on the correctness or relevance of these results, pending more careful reading and thought.

Aha, just realized it's that Bill Press--former (pre-2004) deputy director for Science and Technology at LANL (curently at UT Austin, on leave from LANL).

Oh yeah, link is from The Yorkshire Ranter, who got it from Bruce Schneier.