Everytime I layover in the states I go 'shooting' at a local range and it is all above board. I was stopped at crew search the other day as the 'sniff' machine picked up traces of gunpowder on my crew bag, I told the bemused security guard that this was because I regualary go to a shooting range, after a bit of head scratching he just let me on through. Similar thing happened once when I was on an initial security course for an airline based in Northern Ireland, as part of the course a few types of simulated explosive were passed around so that we could see what they smelt/felt/looked like. One of our guys got stopped later that day when a sniffer dog at Belfast City Airport smelt the familiar 'almond' smell of explosives, after a few explanations he was allowed to continue on home. What can security do if you actually have a legitimate reason for triggering these sorts of tests, I would happily go home everytime I get a 'positive' on a test like this, the reality however is that in most cases you are allowed to carry on with your days work no matter how much a reporter may not like that.