I've not seen it,but don't doubt Rachel. These snails are being studied and might end up on the limited/banned list. They're very hardy, and while they don't breed as fast as ramshorns, they are steady reproducers if you have a male and a female, and their predatory behavior could be serious trouble for native fauna if they were released. They will bury themselves in deep mud to survive cold temperatures, so could be a serious problem. Hence the caution regarding spreading them inadvertently--most people don't check their plants for assassin eggs.