I wish we had those ones at work! (We've got them in our employee IDs for entering the building, and I have bonked my knee on a couple occasions doing the badge-reader door-unlocking dance.)

I think the conclusion I'm coming to is that medical-record implant chips aren't, in and of themselves, a terribly worrying idea. But they're related to things that can be worrying, so if someone (especially the military) is considering using them, privacy concerns need to be clearly respected and boundaries established early. And I don't think I can tell from the article in question whether that's the case or not.