Aahhhhhhhhhh........Your so right,just took a quick course in PIR and see what your saying,oh well there goes that theory.I' m sure they can smell the film and electric parts so all you can do is use some carbon sheets to absorb odors and activate every so often and leave out in an area long enough to descent in outside air.Maybe they just aren' t spooky up here but very seldom ever get a pic that shows any alarm.I use woodwatchers with samsung cameras and pir' s.Very scent carefull when going to cams and checking them,try to leave minimal ground scent(rubber boots)and keep cams out from June to November(never bring them home or anything,just move from one spot to another).Good Cammin' and keep the batteries fresh
woods