If you are an alien civilization, and you are going to invade Earth just for the hell of it with no particular plan to hit major cities or anything, it would make a reasonable amount of sense to start in the Old West:
Of course, it's a great idea to make sure that Daniel Craig and Harrison Ford are not in the vicinity. And Clint Eastwood, too. I feel like, shiny bracelet or none, Blondie would cause some alien life forms some serious trouble.