To answer some of your points:

1.) The "size" of a company is irrelevant. If a relay is "rape-able", then whether the ISP has 400 customer or 4,000,000 customers, the mail server in question still is abuseable. Also, it should be noted, that even companies with millions of users manage to secure their mail servers. Yahoo, for example, has SMTP servers that can be used by Yahoo!Mail customers, which can literally be accessing from anywhere in the world, but those mail servers are still secured against open relaying. Any ISP who claims that the issue is "too big for them to deal with" is deluding themselves and doing their customers a disservice.

2.) I can honestly say that using ORBS on my mail server yields FAR more "spam-kills" than it will ever dream of achieving in "false-positives". I probably average about 1 or 2 pieces of spam per week. PER WEEK. I know people averaging ten times that per DAY. ORBS, combined with something like the MAPS DUL (Dial-Up List), which prevents a dial-up account from connecting directly, has nearly removed my spam load. While admittedly, there ARE going to be "innocent" e-mails blocked, this is a good thing, because then those users will either (a) leave their current provider so their mail isn't blocked, or (b) convince their ISP to secure their server against relay-raping.

3.) On the "original ethics" issue... Eric Allmann made sendmail "relay by default" in the early days because there, frankly, weren't that many SMTP servers around. You couldn't guarantee that your point-of-access (school, business, etc.) was going to provide one, and so people ran public SMTP servers as public-services. Even Eric has admitted that in today's society that won't work. Unfortunately, today, people have abused the good-will of others and the good-will is no longer available. Is it sad? Yes. Is it a fact of life, though? Yes.

Now, honestly, I don't know if we want to get into the whole "ORBS is good!"/"ORBS is bad!" debate, but the reality is that its an issue that isn't going to get solved here in this forum.

D