the definition of total incompetence

from today's papers:

Meanwhile, in some neighborhoods, the U.S. took "every military-age man into custody." An informant then walked around deciding who could go free by pointing his thumb up or down. Such informants have something less than a perfect record. "We almost never get anything good from them," said one GI. "I think they just pick people from another tribe or people who owe them money or something."