One comment with file-robots is that the recipient needs to be verified
with a confirmation message before the data-dump begins (which is also
unique from other auto-response apps).
A lot of mailing list software (majordomo/LISTSERV, to cite specific
examples) do this, too, before subscribing the user -- so this isn't
completely specific to file robots. And some active mailing lists will
cause a larger data-dump than most file robots!
-d