[Brian]

The calendar export feature was implemented in the pre-iOS 4 era as a way for folks to get pop-up alerts on their iPhones. You'd export the reminders to a calendar file, then have the calendar app on the phone subscribe to that file so it could pop up the alarms at the appropriate time.

The Mac app added the feature later, but it was initially designed with iPhones in mind.

In other posts here, you'll see folks that don't want to sync every day, or even every week; the two-week limit is intended to help those folks, while still allowing them to get the reminders if they want. We didn't want to go out too far, though, because that could cause sync times to grow too much. Exporting every item in the database that had a due date attached could have that effect.