I have seen hunters use tree stands for elk but only after a lot and I mean a lot of scouting to figure out their patterns in the area.  The problem is where they are traveling today quite possibly will not be the path that they are traveling tomorrow and it could be along wait.  Now if you can find a nice water hole where they come into every day then I would just put up a ground blind and wait them out. 

As far as them being stolen, that is quite possible with anything that is left in the field over night or for a week without it being used or checked on.  Also if you did leave one up don't be surprised if you come into it one day and find another hunter using it. 

Well, I cannot speak from my own experience, like Critter or others could, but I have seen it from time to time on some shows.  Like Critter says, it's about patterning them.  The places I saw it done were near wallows and water holes.  I imagine it would be better in warmer weather, where they would be coming in to those areas on a daily or semi daily basis.

As for getting it stolen, those are just the chances you take when hunting on public land. I would love to think that all hunters are ethical people, and wouldn't mess with other people's stuff, but unfortunately that's not the case.  Treestands, game cameras, and other stuff comes up missing all the time.  The other thing you have to think of, if it's anything like out here in the National forest in San Diego, is that alot of public lands have laws about treestands left out.  Many state that if it's left out more than 24 hours, it's considered "abandoned". The park rangers will actually take them if they find them.

Still, if you think you found a good plot of land, you have to do what you think is needed to get yourself an elk.  Try all the tricks out there in your book, and good luck!

I would say if you are hunting an area with a resident herd and have a specific limited water supply then using a tree stand just may be successful.

As for the stand's security - purchase an "uncuttable" chain and and "uncuttable" lock mechanism to secure it.  You can find suppliers on the internet for these.  While not truly uncuttable - you need a blowtorch to cut it - these will most likely keep your stand secure.

It would be hard to tell if a bow hunter in a tree was hunting deer or elk, without talking to them.