I've had good success so far (knock on wood) using cable locks and removeable tree steps.

Last fall I had a set of my treesteps stolen and they tried to get my stand as well, but it was cabled to the tree. Unfortunately the thief came back at a later date, climbed the tree with no steps, and stole the STRAP off my stand, but at least I still have the stand itself. I put some removable steps into the tree this year, threw a new strap on it, and killed a deer out of it tonight. While I don't particularly enjoy putting on steps every time I go out, it has become a necessary evil in these parts. After losing 3-4 stands in one season a few years ago I became very cautious of where I put my stands and how I secure them.

When using my Lone Wolf sticks I generally take the bottom two in and out with me as I hunt. With the price of a good stand and set of sticks it's just not worth leaving them out there for any yahoo to run off with. Fortunately the Lone Wolf sticks are a breeze to set up and take down so I don't mind doing it.

As someone said - if the thief wants your stuff bad enough they're going to get it. These suggestions I made are more of theft deterrents rather than theft solutions. My only hope is that some day I catch someone trying to steal my stand in the act so I can find out exactly who it is and why they're doing it before I have them arrested.