It's clear that you're one of those admins who doesn't
see a problem
with throwing out the real mail, so long as you get rid of all the spam
at the same time. I wouldn't hire anyone with that attitude, it's
wilful sabotage.
It's solving the problem. Guess how internet routers solve packet
overload - they throw random packets away.
I run a business, I can't afford to lose a client, even a
potential one,
because the mail got rejected, or the phone wasn't answered, etc. I
know some of them won't retry, I know regular clients who won't retry, I
usually don't retry...
There is a difference between throwing email away without the
consent/permission of its owner and throwing it away with the consent.
The people to whom I provide email are more than happy to lose the odd
real email so they don't have to read through all the spam and are far
more productive as a result.
Also your client case is a bit spurious, most people whitelist clients.
Alan