action mailer delivery errors

hi,

i've been reading up on action mailer in AWDWR 1st Ed. my rails app has
a mechanism for reporting issues with the app and mails it out to
support people. the book says that with
Action::Base.raise_delivery_errors = true trying to deliver the email
will raise an exception if the email can't be sent.. it also says that
in some cases there is no way to know if delivery was successful.. like
if the email bounces because of a bad address or mailbox is full or
whatever have you. in my situation the email bouncing because of bad
address or full mailbox is very unlikely. each issue report record will
have a flag to indicate whether it was delivered or not.. i really
don't want a record marked as delivered if it didn't make it to the
recipient.. are there any other situations other than the ones i noted
above where an email won't get delivered and won't raise an exception
??

thanks in advance,

stuart