Proximity Crimes In Iraq

The New York Times has an interesting article detailing a day in the search for the three missing soldiers. In one day, one soldier is killed by a land mine that also wounds others. A second soldier is killed by a sniper's bullet. The soldiers forge forward with courage and determination.

An interesting tidbit contained in the article involves the arrest of five Iraqis who are in a building near where the land mine took the life of the American soldier. They are checked against a list of suspected insurgents and found not to be listed. They are arrested anyway purportedly for being in the "proximity" of the bombing.

It struck me as an odd tactic likely to net many innocent Iraqis and create animosity toward the Americans and Iraqi security forces in those wrongly jailed as well as their families. On the other hand, proximity arrests probably take a number of actual insurgents into custody.

My question is whether there is any evidence or studies that support this tactic. My initial thought is that it sounds likely to be counterproductive.