why shouldn't they? they have ears and probably a version of nanovision. search around for a rocket launcher or hoy a few grenades at them.
That's what I was doing. But you have to get behind the tripods. And to position yourself around the map and get behind,just for it to turn around so you have to do it again is annoying.
If they had nanovision then they'd follow you around the map,they wouldn't turn around just as you got behind them.