I applaud your creativity. Like codingpanda said, there would require some way to stop the cheating. Besides simple attaching a device to the dog's collar or something, there'd be those who would create an artificial changing signal to feed in to the system that would appear to be moving. This is a great place to share innovative ideas though, so maybe someone will think of something that works sometime and you can be like "I thought of that idea, its even etched on the graphene (steemit) blockchain" :)