The last 2 events there has been complications with the removal of the event of just unexpected dates.
The Easter event there was communication issues within the team, or so it seemed and not everything on the event forum post was correct (for example explorers that where sent off before the event would still find eggs, this did not happen and messed with quite a few peoples progress)
The latest event seemed a bit sudden. Usually there is some sort of notification on the homepage but the only date available was on the forums. To go to the forums each time to find such dates is not a very good system. For someone like me who was abroad working through most of the event to only have gems I spent on the tokens to be removed the next day, I just feel that these situations can easily be avoided by having more communication with the players in the game itself.
Possibly a small event countdown in the corner of the screen, or a message as you log into the game. There are plenty of other ways but my main suggestion is to bring better communication from the forums to the game itself so we the players don't have to run about looking for details.
Thank you.