Well, I should have said I hope you're not using export as the only method for purposes of backup. If you are, you have just reduced the limited effectiveness of exp.

Using export as the only method of backup is a big no-no, IMHO. It limits your options for a recovery in so many scenarios. By using CONSISTANT=N, you are limiting yourself even more because your RI will most likely be out of whack in an active database.

Since you're using hot backups as the primary backup method (you've tested basic recovery scenarios, right?) and use the exp as a supplemental backup, you are covered for the overwhelming majority of failure scenarios.