What I'm seeing a few times in Push is that a defender will pick the demolition class and equip a rocket/rpg. Once the match starts he immediately runs as far as the restricted zone will let him and takes a shot at the technical that will inevitably be driving up the road, killing 4+ players. Once that's done he will retreat and play the game as normal.
I see this as cheap, but am also mindful that the driver choose to take that route instead of a longer flank.