As an employee of a Lines Company here, it's not the actual theft that worries me, it's the shambolic ways that people use to effect an illegal connection.
I was at a house about 6 years ago, this place has always stuck in my mind for some odd reason, the ripple relay was missing off of the switchboard panel (the panel was on the outer wall of the house, but under cover).
I asked the lady there where it was.
The reply was that her husband had moved it up into the roof, because "it made a funny noise and kept him awake".
Sure enough, get up in the roof and there it is, lying on top of some roof batts and some strange wires coming out of it too.
Traced the wires over to the other side of the house, fed into an air-conditioning unit.
When asked why this was, I was told that her husband was an Electrician and she had taken that he wired the A/C unit into the switch-board when he installed it.
I disconnected the unit and put the ripple relay back on the switch-board.
I left a note on the front of the relay stating: You have been found out, please call (cell no.) for more info and told his wife not to let on, but only tell him that the A/C unit wasn't working.
Guy in the end had his licence suspended for a year over that.
So it goes to show, even registered people can get caught out.