What if it's a tie?

I don't think that would be fair at all. The DNC specifically made it so that Florida and Michigan would not get any delegates, because of the fact that they wanted to change the time for their election. Counting the votes from the two states would put at a disadvantage candidates who didn't campaign strongly there, due to those before reasons. The Democratic Party made that decision, if they went back on their word (their decision), it would be just as bad as if they didn't nominate the candidate with the most popular votes, and let the superdelegates decide. I really don't think they will come to that, hopefully we'll have a decision way before the convention, but let's see!