See How to Remove or Change the Reminder on All Day Events for the basic code. You can use VBA to not set reminders on events in specific folders. Unfortunately, unless the calendar is in a different data file, you won't be able to disable the reminders using options within Outlook. These appointments are always in the past and now they always trigger a reminder unless the user remembers to deselect the reminder.
We also receive complaints about this feature from users who were in the habit of creating appointments in a secondary calendar folder to use as a journal. We have a tutorial at Change reminders on several items. If you need to keep the flagged items in the To-Do Bar and only want to get rid of the calendar reminders, create custom list view that groups by reminders then drag from the RemindBeforeHand:Yes group to the RemindBeforeHand:No group to turn them all off. If you don't see the option, the data file is used as a delivery location for an account or is the default data file. With the enabled, you'll get reminders, with it disabled you will not get reminders and tasks or flagged messages will not show up in the To-do Bar. Just above the folder size button is an option to 'Display reminders and tasks form this folder in the To-Do Bar'. To change the setting, right click on the top level of the data file and choose Properties.
