How did this happen?

http://news.bbc.co.uk/1/hi/world/europe/4074101.stm

Apparently the French were using real passengers' suitcases to train their bomb sniffing dogs by places plastic explosives in them, and they lost one of the bags with the explosives, so now its at somebody's home. Worse, if that person had had their bad rescreened, they would've have been in serious trouble. Also, all the bags they did this too will now be detected by dogs and/or electronic sniffers for a while because traces of the explosives will remain. Good Job! Of course the TSA has missed guns and other things, so we are no better at this.