There is a couple of reasons.
1. The location is secluded and has little car traffic unless it's a weekend.
2. The demographics of that area indicate that the bogans that live in the vicinity (eg;Rockingham,Kwinana,Hamilton,Beeliar,Munster) are lowlife trash who prob don't work and need their fix of weed or Ice.. So they'll steal from easy targets and sell their gear at Cashies.
3. There are no security CCTV cameras there even though this would be a good idea
4. Kiters are easy targets, the either leave their personal gear in their car and risk getting it stolen, or one the beach and risk getting it stolen. Catch 22 really.
Summary: A lot of people these day including a lot of Kiters have manginas, who don't like confict and find it difficult to react in a situation if they experience it. You would think they had any sense the would rise up in a group against these thieves. Do a stake out and use some 'Trail Cameras' which have been placed in the Imidiate vicinity in order to catch these thieves. It's been going on for years and without a deterent or action there will be more this summer also. I'm glad I don't like in the Metro area anymore as this tends to happen far too often.
Maybe a solution is for everyone to throw in some cash and set up some cameras in a discreet location.. Waksa??? Ummm nope, too hard basket, what about Laurie... Surely he is doing well off advertising and PAy per click on this site to share the love...
Raise a few grand, install your own camera overlooking the problem area...
