According to court papers referenced in this VOA report, U.S. sniper teams in Iraq are using an interesting tactic:
[A] so-called baiting program developed at the Pentagon by the Asymmetrical Warfare Group….the baiting was described as putting items, including plastic explosives, ammunition and detonation cords on the battlefield then killing suspected insurgents who picked up the objects.
These claims are being made by men accused of murder, so bear that in mind. If true, however, this technique would seem very likely to suffer from a large number of false positives. Assuming the process was designed by someone intelligent, that either means they do not care about false positives, or that (contrary to my prior belief as asserted above) the likelihood of a curious true bad guy happening by is so large that the false positive rate is tolerably low.
Scary either way, I’d say.