Hope it's not legal to put drugs in unsuspecting passengers luggage here - good grief, even if the person manages to get out or the airport or connecting flights without getting pinched and serve jail time, etc. - and find the drug and destroy it or turn it in - their bag will forever get a hit from a well trained dog...
I seem to recall something like this has happened here in the states?
I seem to recall once or twice test items have been lost in passengers' luggage. I usually "lock" mine with small cable ties just to tell if someone's been in it. Usually when the tie is missing there's a notice inside -- usually but not always.