I can understand the motivation, legality aside, but the implementation seems irresponsible to me. A device like that will very likely annoy, if not anger, dogs

I can understand the motivation, legality aside, but the implementation seems irresponsible to me. A device like that will very likely annoy, if not anger, dogs at distance. My old cats could hear two rooms away a 40 KHz signal played by a piezo transducer directly connected to a function generator with no amplification in between. An old ultrasound TV remote had the same effect. And cats hearing although better than ours is less sensitive than dogs'. I can't imagine what level of discomfort that device could put on cats, dogs, bats and other animals.