I'm wondering just how prevalent these have become, particularly on the continent - does anybody have any experience?? I have read of two or three incidents involving narcotic attacks, but they do seem to be few and far between. It's nearly time for my annual couple of months in Europe, and I'm wondering, should I be worried? As far as Narcotic attack alarms are concerned - do they work, or are some, as I suspect just butane/propane/CO2 alarms/hydrocarbon gas alarms rebadged as narcotic alarms?? I'm guessing that a proper 'Narcotic alarm' would have to be pretty sophisticated given the spectrum of noxious and poisonous gasses that could be used in an attack.