1. A method of determining a measure of likelihood that a designated wireless device exhibits at least one pathological characteristic, the pathological characteristic causing errors in position estimation to occur when the designated wireless device is used as a landmark in a position estimation system if left uncorrected, the method comprising: based on information from signals received from a designated wireless device, retrieving at least one of (i) an identifier representing a manufacturer of the designated wireless devices and (ii) an identifier representing a model type of the designated wireless device; and determining a measure of likelihood that the designated wireless device exhibits at least one pathological characteristic based on at least one of (i) the identifier representing a manufacturer of the designated wireless devices and (ii) the identifier representing a model type of the designated wireless device.