SmarterMail guesses as to whether or not
there is an attachment in an email based on the content-type of the
email. This method is more efficient than parsing the entire message to
determine if it has an attachment and it is right in most cases.
SmarterMail has to balance how things work with how efficient they are
when implementing webmail features - and this seemed a reasonable
trade-off from the SmarterTools point of view.