I worked with a lad once who used to fill boxes up, the sparky then used to come along and smash the boxes with his hammer to get the plaster out, the spread then used to come back and patch around the boxes, consequently his work looked s**t, and he used to get the blame for it cos its his plaster. Funnily enough he now works in a factory because no one wants him on their jobs.
I cut all wires back, re-mark and tuck into the box, once skimmed i clean the boxes out, and clean the wires ready for the sparks to 2nd fix. I agree they're wankers, but it takes no noticeable extra time to sort and leaves the job tidy.