When they lost signal, the process of fixing and returning them causes more unnecessary inconvenience and problem.
In addition, a famous fiction movie called “EX Machina” tells a terrifying story that a scientist is killed by a human-like robot produced by himself, while his original intention to design such a machine is just simply assisting him with housework. When the robots have more mature artificial intelligent which is exactly what people desire, it is rational to assume that they can acquire the incentive to offend, even hurt their masters just like what people do to each other. Although it is a science-fiction movie, the thoughts behind its story definitely deserve the public careful concern. The dangerous and limitation of robots are still available so that we should use them as prudently as
possible.