Well,

it depends on the event. For example, lets take two events here in Colorado (a) Elephant Rock and (b) Triple Bypass.

The Elephant Rock is flat for the most part, and overall you should be able to do the century ride no problem. I have not heard of someone having to SAG back to the finish line. But the Triple Bypass often has people who just cannot finish it.

If there is a chance you might not finish the event, do not wear the jersey until the day of the event.