Helping the rejection committee
Liz quotes a friend who sold expensive business to business products in Texas, "It's not a no until they call security!" This salesperson has no intention whatsoever of helping the folks who reject her do the rejecting.
I'm not sure you have to go that far, but I know that many marketers work hard on behalf of the rejection committee. We sabotage our college applications or email pitches or websites, predicting in advance that we're not going to make it, not good enough, not worthy. So we set out to save them the trouble of having to think hard about the no.
If someone wants to say no, let them. But no need to help them get to no before they get the chance. Let them do their job.