The fella complaining is a small business with hundreds of thousands of customers.

It's "too much trouble" to keep track of who's opted in to receive mail and who has not. All of his customers are loyal and have "a previous business relationship", i.e., they bought something from him.

So, let's say that he's compliant with the CAN-SPAM law and actually has a valid removal address. Even though it's "too much trouble" to keep track of those hundreds of thousands of email addresses he has somewhere one might guess that he might actually remove somebody's email address upon request. Unless, of course, the next product offering he plans to deliver is really, really important. Hah.

This is spamming. Spamming is Unsolicited Commercial Email. It is considered bad practice to respond to such emails because (1) spammers lie and (2) see #1.

If he was really interested in not being considered a spammer then he would use the Confirmed Opt-In protocol. That's much like the way you run your new account creation, Mr. Foster, where if a $RANDOM_MISBEHAVING_SCUM signs up people for accounts the worst that can happen is that people get one email saying, "Here's your request. If you don't respond, you won't see another one." If one does respond, then there's a record that the emailer has saying that the respondent wants email. If not .. Well, spammers can sign up anybody. And $RANDOM_MISBEHAVING_SCUM can be anybody, like, for example, the advertising/marketing people in his own company.

One last thing. By his own admission, his company sends out email, say, several times a year. His position is that it's not often enough to be considered spamming.

At last count there were several tens of millions of companies in the U.S., never mind the rest of the world. Even with small percentages, if all those companies send out email for "invaluable opportunities" once or twice a year, one will find thousands of emails a day in ones inbox.