At my local Dollar General store they have one of those remote door bells buttons sitting on the counter. When you are ready to check out, you ring the door bell and the little gal comes running. I don't know how much those cost, but I would think you could maybe rework the thing to trip a shutter. If not that, if you could find a junked car with the remote lock system, and the key fob to go with it, then you would have a camera tripping device that only one in 100,000 honest people could use to trip your shutter. Or, one in 10 crimminals. There must be other remote devices that could be used to do the deed. Ric.