@leprechaun Some enterprising young entrepreneur kills them in their sleep and then markets himself as an accomplished security professional. :P (Note that I personally do not support this solution, but it would be effective, and it will be used if the problem persists)

Alternatively, in the information age, that all happens, and that's fine and good until someone blogs about it, it goes viral, and the thieves can't buy food anymore because no one will sell it to them.