Nighttime Vision Goggles

Is there any reason why someone would need to wear Night Vision goggles when walking around their neighbourhood? I'm living in a (pretty) regular Sydney suburb and twice now I've seen a guy looking like he's just stepped out of a supermarket carrying his shopping, wearing these goggles. Unless its two different people, in which case maybe there's some sort of club. I guess these could always be some sort of experimental bionic implant, but I doubt it.