Steel cage for AC unit?

[Allen L.]

After reading stories from landlords about AC units been stolen and sold on the local craigslist for 10% of replacement cost, I'm contemplating whether to steel cage all my rental's AC unit. Has anyone done this and how effective is it in deterring thieves?

Also,

What is the material and labor cost of installing steel cages?

Do you think thieves tend to steal AC units that are installed on the side of the house therefore easier to get away or do they also steal units placed in the backyard (assuming yard is not locked or un-fenced)?

Are there added costs of repairing and maintaining AC units because it will be more work to remove, do work, and put it back into place?