I've given this map to half a dozen smart/well educated Canadians, who happily engaged in pointing out the states they recognized for several minutes, and not one of them noticed until it was pointed out.
I'm from the UK and would probably have fallen for this for several minutes as well. I hope that I'd eventually realise from the number of states down the West coast.
For anyone else who is geographically challenged, the map apparently has 64 states instead of 50. Here is an article with the extra states highlighted.
Quick, label all the US states: https://imgs.xkcd.com/comics/label_the_states.png
I've given this map to half a dozen smart/well educated Canadians, who happily engaged in pointing out the states they recognized for several minutes, and not one of them noticed until it was pointed out.