Seems to me that blocking an entire area code or zip code, while extreme,
would be an incentive to those in charge of the area or zip code to get
their house in order. In this case, it means that they need to police those
they're selling services to, and to quit looking the other way at
downstreams that spam or offer spam support services (e.g. "remove"
services, hosted advertising, email) rather than chase the easy money
associated with pink business. It's probably the only thing keep even more
providers from selling out entirely to spammers, IMO.
but the blocking out of entire domains of legitimate
ISPs is as bad as
the SPAM; it's equivalent to the telephone company blocking out
incoming calls from entire area codes, or regions, because of
telemarketers and seems to defeat the purpose of e-mail, or the
post-office banning the delivery of mail from entire zip-codes or
regions.