If you place an AT mine on a buildable such as Rally Points or Barbed Wire when they get destroyed the AT mine automatically blows up with a great explosive radius. This also applies to Medic Boxes and Ammo Boxes, specifically turning medic boxes into IEDs as everyone likes getting easy points shooting medic boxes due to their low HP.
Another related tactic is placing a sandbag in the middle of the road with an AT mine behind it. Needless to say newer players will always run it over.