It will be interesting to see the repercussions of this. A lot of people woke up to ~2 hours of what was probably quite frightening. Anyone nervous of living in the area is probably considerably more so now.
Adding erroneous nuclear alerts into the experience isn't going to make people feel very secure about the service or their neighbourhoods. People will just change their alert sound to silence, or something that won't wake them up even in the case of a real emergency (that boy who cried wolf you mention). Then it expensively helps no one.