[stoney]

The article did say at the end that they've put in measures to stop it happening again. Presumably something along the lines of monitoring usage per SIM. I would guess that it just didn't occur to the power company or Telstra that someone might steal the SIM and put it in their phone.

If I stole a SIM card and used it to download movies, I would fully expect to be liable for the cost of the data at whatever rate the SIM owner had agreed with the telco.

In this case the thief (or really the recipient of the stolen SIM) was unlucky that the data plan was a B2B contract designed for small quantities of data.