Yeah,
That happens quite a bit down here.
Some people seem to forget (or ignore) the fact that aluminium foil is an electrical conductor.
I remember a few years back, going to one of the local scout dens where a plumber had recieved a 230V shock while climbing under the floor through the man-hole and touched the foil that was live at full mains voltage.
It took ages to find the fault, because the staple had only pierced the phase wire in the cable.
BTW, this sort of insulation is only used in the under-floor area of buildings, not up in the roof void.
