[Dovecot] Dovecot discards mail over quota

[Seth Mattinen]

It's simply a fact these days that people find backscatter and 
misdirected bounces annoying. In many cases they end up at a forged 
address that had nothing to do with the original transaction. A well 
behaved receiver will make decisions during the SMTP transactions with 
appropriate response codes. It should never accept and generate a 
message later.

It's not a matter of mincing what an RFC says or does not say, it's 
about not being a dick on the internet and respecting your virtual 
neighbors. It's like if you were to go through your postal mail box, 
separate the junk mail and throw it into your neighbor's yard.

~Seth