From reminders you can view individual reminders by clicking their dates. This allows you to see who else has been assigned the reminder, who has read it and when it has been read. Now, just because they viewed the reminder doesn't mean they really read it.
Seeing the list of reminders on Reminders does not mark them as viewed, only when reminders are individually viewed are they marked as viewed. Clearing a reminder does mark it as viewed.
Please call your Red Carpet Professional if you have any additional questions.