In response to closing
MDL-18300, I am opening this issue. Currently, for rating, if the forum restricts ratings to items with dates in this range (ie there is an assesstimestart) that information is not shared with the student. Since this can serve as a bit of a due date, it would be good if at least when viewing the forum information that it was also shown that only forum discussions/replies between the start and end times will be available for rating/grading.
While my primary interest is getting this to work with forums, I also noticed while doing a grep on assesstimestart that similar functionality is used in the database and glossary activity modules so I will add those for now as it may be best to introduce this functionality in one patch all at the same time rather than opening different issues.