RPG magnet but, hey, any armour's better than no armour. And you have to give them props for waking up one morning thinking 'This infantry shit sucks, I'm going to get all Mcgyver and build my own tank out of a PS3 controller, an RPK, a Kia Shitbox and a bunch of metal.'.
As long as that doesn't morph into 'I wonder if I can take out a T-72?' Ooh, great idea, strap a bunch of RPG's or SPG-9s to the top – instant Ontos.