I suspect these might not have been vandals, more than likely they chopped into the cable to steal copper... Fibre cable and "old" metal based cable look very similar when they're all covered in the weather proofing and armour.
Only after they completed the first cut would they be able to move the cable enough to discover they wouldn't get anything more than some posh glass from these particular ones and gave up.

So yeah, once again well done Telstra.

With the quality of broadband services in sydney many in the area wouldn't have noticed.

Does this have anything to do with http://www.flickr.com/photos/amdfangirl/2467563012/

Well not really.
The main goal of hacking is to take control, to use the target once the hack is successful.
Cutting the cable does not count as a hack since there is nothing left to control once the cable is cut.