The confusion over tournament end dates is nothing new. I'm pretty sure that they are aall posted in the same manner.
When it says June 1-July 1, that means June 1 TO July 1 ... not THROUGH July 1.
Unless someone is a total newb, there's not a lot of excuse for making that mistake. I'd think that most of us have missed getting a weekly round finished at least once or twice because of the confusion.
The bigger trouble has always been the time zone thing.
Like Minky said, a countdown timer would be a great addition. We already have it for the CDP and CC tourneys show the time left to play, how hard can it be to do the same for every tournament?