If the person aint too mechanically minded and the cars a bit older then chances are the bleed nipples are gonna be a bit tight and may snap, id say it was easier to take off the reservoir cap mysel mate - personal opinion tho.
Another way of pushing the piston back is to stick a long screwdriver through the "gap" at the top of the caliper and across the piston and push rather hard. Dont push the piston back too fast or you may damage the seals!
Daz
