I received something in my email this evening which I initially thought must be a hoax, but apparently it isn't. You can check out this link at snopes.com for details.
So what is the warning? This applies to Republicans and Democrats.
Apparently, some states have a category or box for those who wish to vote a "straight ticket." What is not made clear is that in some states, although the ballot doesn't indicate it - the Snopes report cites North Carolina - the office of President is distinct from the straight ticket category. In other words, if, as a voter in North Carolina you vote "Straight Ticket" and think you have voted for the President, you are mistaken. You have only voted for all other offices. The vote for president must be cast separately. You must mark, click, whatever your presidential choice AND straight ticket. This apparently varies from state to state. I don't remember ever seeing a straight ticket option on the New York ballots, but it may be there.
I really think we need major election reform in this country. Such things simply should not be possible in this day and age. We really should be able to trust that our vote will be counted.
Addendum to original post: My niece Diana lives in North Carolina. She said that the ballot is in fact set up this way. She voted yesterday and said that in her district, at least, the ballot is clearly marked. They have paper ballots and you can double check and correct your ballot if you make a mistake. I was glad to hear that.