Fascinating, I thought it was the finned bullet but this doesn't seem to be that. There was an interesting, if somewhat forgettable, movie staring Tom Selleck called 'Runaway' which posited "tracker" bullets and use the of quad copters for remote surveillance.

I expect the next step will be fabrics that fluoresce in the visible spectrum when hit by IR or UV laser light to help warn people they are being 'designated.'