Our website has a check box that while in the checkout process for purchasing a product,
the customer "Opt In" to getting marketing emails from us.
It's possible that someone who purchased in the past, may have been on our list, and they were removed for some reason.
But now they are making a new purchase.
Can I consider the "Purchase" and Check-Box, as an ACTION_BY_CUSTOMER and re-opt them into our list?
ACTION_BY_CUSTOMER is an action that you would use when you are referring to yourself as the site owner of the account. This will not opt anyone back in that has previously un-subscribed. You would want to use, "ACTION_BY_CONTACT" as this would be the action that the contact takes when they want to subscribe or un-subscribe. By setting it to CONTACT, they will receive a welcome letter to notify them that they have been added.
To rephrase then:
Can I safely use "ACTION_BY_CONTACT" when the "action" is their lack of un-clicking a re-subscribe me to your list upon making a purchase from our site?
Maybe this is something for the "Terms of Service" people, I don't want to break any rules.
You wouldn't really want to make them uncheck the box as that is not best business practices as if someone does not see it then they get your email and mark you as spam. I would have it remain unchecked with maybe the safe unsubscribe logo which makes people feel comfortable about putting their email in your hands. But the ACTION_BY_CONTACT is the appropriate use for that type of application.