Bart, there was a link in the post Trolkiller was quoting, as was clearly apparent to anyone who can read. According to the figures in that link, 160,000 people have been harassed by BDOs, and only 1,266 arrests have been made as a result of this harassment, and vast majority of those were for things like fake IDs and drugs, none of which have anything to do with security. 1,266 divided by 160,000 is 0.0079125, which means that Trollkiller is right to say that the BDO has a false positive rate of over 99% and is thus prima facie useless and does nothing to make anyone safer.