Earlier quoted context omitted.
> We were also informed that our normal, business communications with paying customers should have unsubscribe notices appended to them. Which is to say, you're a paying customer of a service and we send you some kind of alert or critical announcement ... and it should have an unsubscribe link. You absolutely should. The amount of junk I get because someone else signed up for something and fat fingered their email ad…
That's a (very legitimate and important) reason to do double opt-in unilaterally for all email communications. Companies should make 100% sure that the person who signed up, and the person receiving the email, are the same person, before they associate the email with the account. Otherwise, malicious people can sign up arbitrary third parties for tons of random crap. But it's not a good reason for adding unsubscribe…
1. Forget I had a monthly power bill for a couple of months.
2. Ignore the e-bill that gets sent to my bank bill payment service - ebills have been a thing for almost two decades. I worked on some of the early implementations.
3. Ignore the physical snail mail warnings for a couple of months.