A reader asked the following question, "Do you have any tips on keeping your stuff safe at your camp site?". The question was particularly about the tent only area but my answer can be applied to anywhere.
The main thing I do is not leave anything real valuable at my site. I leave most of my $ and cell phone locked in my truck. In the morning I wander over there, get any cash I need, call home to let everyone know I'm still alive, then lock everything back up. Another (obvious) thing is not to leave valuable stuff in plain sight. There isn't a lot of theft from campsites, but what theft does occur is usually just people grabbing a bag off of a chair or from an open tent as they walk by. If you are camping in tent only, I'd advise not camping right along a road or near a corner of the space where a lot of people will cut through. The less traffic, the fewer people walking by who might grab something.
I wind up bringing a decent amount of stuff so I keep most of my gear in a locked medium sized Actionpacker cargo box that I drag to the campsite. Theoretically someone could just boost the whole box and then try to break it open but most thieves at 'roo are just going for the low hanging fruit.