I don't think I can even count the number of times I've seen events advertised incorrectly; yours was done correctly, which is probably what caused the confusion!  I think a good rule of thumb for ECs out there would be: *never* start an event at 0000Z. I like your 2359 solution.

Cheers,
Ben

Actually, the event was posted incorrectly. The only place in the world that the day would change at 0000z is at the dateline. So, if you were standing in London, Dublin, Edinburgh, Lisbon, Reykjavik or Casablanca then yes.... 0000z would turn the date to the 17th and 2359z would still keep you on the 16th. However, if you were to stand in Colorado at 0000z ( GMT -6 ) then the current date and time would still be 1800MDT on the 16th of the month. The only confusion is people think that 0000z magically turns the date to the next day everywhere in the world.... which it doesn't.

If you were to post your event at 0000z on the 16th of the month pilots would know to be there at 1800MDT on the 16th of the month... because it's in Colorado, and thanks to the conversion process. It is absolutely correct to say 0000z on the 16th. 2359z has absolutely no effect on what day it is... that just makes it 1759MDT on the same day ( Unless you're standing in London ). Truthfully... all the other ECs know this and that's why we never have issues posting events on the VATUSA Calendar.  

Hope this helps.
Lloyd O Boyette | EC/MTR