Ok you're right about it not deleting by default. But there is an option to delete mail after its been accessed with POP. And in any case Gmail hides the messag

Ok you're right about it not deleting by default. But there is an option to delete mail after its been accessed with POP. And in any case Gmail hides the message after you've read it, but you could still have an error writing the message to disk and thus miss backing that message up.