Some regions require customers to explicitly agree before their email opens and clicks can be tracked. For customers in these regions, tracking is off by default, and they'll see an option in their account settings to turn it on.
Customers in those regions will see an option in their profile settings that will allow them to opt them in to receive personalized emails from the site that they are part of. Agreeing to this option will permit tracking email opens and any clicks inside of it.
What this is used for: This information is used to understand which emails customers find useful, so future emails can send them more relevant content and fewer emails they don't care about.
What happens if they don't check this box: They'll still receive emails as normal. The only difference is reports won't able to see whether they opened emails or clicked any links inside them.
Customers can change this anytime. This choice isn't permanent. Customers can turn it on or off later from their account's email preferences.