[inciarco]

I guess you can use the same Date and Time Control that vBulletin Uses for the Searchs, because this is a Search it self, so if you Update and Control this Limits with the same System as the Board the User won't be able to Abuse of this Queries and also won't be able to Search Again on the Calendar or the Threads/Posts until the Waiting Time Expires.

(This way you don't need to Create your own Time Control, and use the related one on the Forum Board).

(I saw that the Mod uses the same Permission for Searching, so if an Usergroup don't Have Permissions to Search on the Forums won't have Permissions to Search on the Calendar, that is very Logic because both are Searchs on the Board.)

My Best Regards.