"No backscatter" is a large sledgehammer used to make life simple for over-bureaucratic sysadmins. It's valid in some circumstances, but NOT in all.
I had that argument with my provider. I sent an important business e-mail, using a "premier" e-mail account hosted by them, logged in using secure SMTP with passwords and all, so they knew it was me and only me.
Their system decided that since it was talking about money, and contracts, and the like that it was a spam and silently dumped it. Fortunately, and purely by chance, I found out before it was too late that the message hadn't been delivered. I was livid, given what the consequences would have been if I hadn't checked...
Their excuse for not telling me they'd dumped it was "no backscatter". My argument was "You knew it should only be from me, because it had my secure SMTP access code and password, so either it was genuine - in which case you should have delivered it, or it was a hack of the secure SMTP - in which case you should have told me of your suspicions of a security breach, not just dumped it."
Not even an apology did I get. "Strike one" to that provider.