The reason I created this simple low-tech thing was so that I could go in the water with my wife and friends without having to worry about someone walking by and ripping us off - Period.
Unlike most thefts, beach thefts are perpetrated using a very subtle MO. A thief walks along the beach looking for a target - in this case, an unattended towel with a bag or backpack on it. Once located, they walk by and subtly pick up the bag and continue walking.
There is NO HOLLYWOOD DRAMA...
They don't sit down and rifle through the bag looking for valuables OR noticing that the bag is connected to something – get up and start tugging on it until either the braided stainless steel cable fails OR they successfully pull out the deeply embedded 15" anchor. Both of these actions are too conspicuous!
In reality, the thief will pick up the bag, notice in milliseconds that it is attached to something, drop the bag and continue walking.
It's easier to scout for another target than risk getting caught playing around with a protected one...
ENJOY THE WATER :)