Most of the practices each of us may take to protect our valuables; whether it be locking the car while shoping, or closing up an RV; are designed "to keep the honest folk honest."
Anyone who is intent on stealing, knows how to break into your car or RV, by forcing a door, or cutting through canvas material (that's why I never lock my convertible Miata - just it's console compartment).
When we leave camp for extended time, our thoughts are more on unexpected rain showers.....we zip up the bunk ends facing prevailing winds tightly - the opposite sides we leave open slightly at the side or top.....maintaining privacy, but keeping things aired out. Since our roof vents have rain covers, they are left open.
That said, one of the many advantages of polite introductions to your campground neighbors is that they will more likely take note of your comings and goings and "watch your camp" while you are gone.
Don't leave that mink coat on the clothes line, put a tarp over the gold-plated gas generator behind your RV, and use that bike lock on your diamond encrusted carbon fiber framed bicycle.....do what's prudent not to tempt someone to "accidently borrow" something.
Other than that.....go....have fun....trust that the most honest, nicest folks are the ones who go out camping.
Like another post suggested....if you find yourself at the campground where "bad biker gangs" (not the clubs) crash and drink; cause it's handy to the sand flats, and you feel threatened by their presence......then just maybe you'll be happier if you move on down the road......just saying.
My 2 cents worth.