Just having a date for when you can last collect prizes is confusing. Some people consider it as no longer available on the date provided while others think you can collect on the date provided but not after the date. (Example, the date for this season is December 5th. Some people will think you can collect on December 4th, but not on December 5th, while others will think they can collect on December 5th, but not on December 6th.)
The avoid confusion, please add a time of day to the date.