Screw Mesilla Valley Mall.
For one, they aren't properly posted. NM state law requires any sign stating a prohibition of any activity to be 144 sq in in size. The signs in the mall prohibiting weapons are a one-liner on a long list of prohibited activities on the inside wall between the double doors where it is likely to be missed by anybody coming in, plus any doors into a store (Barnes & Noble, Sears, etc) do not have even those signs.
And in the case of a LEO, it's illegal to disarm a peace officer. You can bet the ass hole rent-a-cops will be arrested for trying. Plus he was in a marked unit, which means he was likely in uniform. I don't know about you, but if I had a police uniform on, I'd be afraid to not have a gun to go with it. It's just begging for trouble.
The deputy was a moron. He deserved to have his duty belt stolen.