For example, you send an unsubscribe message to a legitimate company or a spam, they reply that they will remove you and it may take up to 72 hours to take effect. I find it hard to believe anything that simple could take more than 3/4 of a second to take effect system wide.
Another example would be when you call the visa activation line, there is a “delay” of several minutes while they try to sell you some kind of insurance. Usually just as you get the point across that you don’t want it they will tell you your card has been activated and let you go.
Are these delays real?
The delay for removing an email address is certainly real. It’s common that there is one system for managing the email addresses themselves (and removal requests) and another system for sending mails. As they are not directly connected, the addresses are exported now and then, perhaps twice a week. There is also no real reason to suspect that they are prolonging the process intentionally, as there is hardly anything to gain from it.
The card activation dealy seems more suspect. There may be a certain delay, but as they are using that to try to make a sale, it would be stupid of them to interrupt the sales pitch the second the activation is complete…