yeah, would be simple enough to hide it where it would do the most damage and not be found at the same time. one example from long long ago was guy planted bomb in the basket of a little girls bike and chained it up against a lamp post, when car he was targeting went by he triggered it, there was a couple pound slab of copper in the basket facing the street, the chunk nailed the car, an armored limo, flipped it and took out the guy intended, and only the guy intended, couple injuries, but nothing horrific. Could have been worse if decided to make it a sharpnel one...
All in all the whole situation seems pretty stupid. though if i was in the guys who put those things up shoes, i never would have seen this coming either. i would have atleast try to make the battery pack look like something more then an electical tape wrapped brick of something. maybe even put in the name of the show. eh..