Different rules in different places
One of the more bizarre aspects of an American Election, from the point of view of a European, is the fact the there isn't a standard set of rules. So Obama's dead grandmother would have had her early-ballot pulled if she lived Iowa, but it's counted because she lives in Hawaii. And if she lived in Pennsylvania, she probably wouldn't have been allowed to vote early.
The same goes for the argument above about whether a "straight party ticket" vote includes the Presidential race - it does in some places, and not in others, apparently.
Of course, for European wide elections, each European country uses it's own rules, but then there aren't European-wide elections for a single office, just country-wide elections for local representation in a EU-wide parliament.