outdoors they have infra-red which can detect plants that put out high heat like mary. But I think this is only a problem if you live in a place where you don't have tropical plants therefore the mary will stick out like a sore thumb under infra-red. As for as spotting, that depends on how slow and how high or low they fly and if they are looking for that in particular. I've been on many many choppers and it's hard to spot anything when flying high and fast.