I was actually watching the military channel a couple nights ago. Obviously it's TV, and not 100% accurate, but it said that the IR patches the military uses are the Country's Flag the soldier represents, (a fairly large patch) that has IR qualities too it, they are very distinctive looking, and hard to mistake for a normal Flag Patch. (what what I could tell from the video).
They are restricted FOR SALE to the military only. So if you can buy a patch, your well with-in your right to wear it. [smilie=armata_pdt_18.gif]
Of course, there's always the possibility that I'm wrong.