EC: Require Confirmed Address

Please explain what PayPal and Zen Cart do when the Require Confirmed Address is "Yes" and when it is "No". I understand it applies to non-logged in customers, but what is the customer entered shipping address in PayPal confirmed with or against? Does it mean checking the shipping address to see if it is "real" and not a fictitious address? Or does the shipping address need to be in the customers PayPal account address book? Does this control affect payment only with a PayPal account, or does it also apply to customers who enter credit card numbers, billing and shipping addresses as a quest? What are the advantages and disadvantages of setting this control to No?

Other PayPal EC settings: Payment Zone - None, EC Shortcut button - On, PayPal Mode: PayPal

Store location: US

In your store's Express Checkout settings, when you tick the box for "Require Confirmed Address", you tell Zen Cart to tell PayPal that you want PayPal to ensure that the customer's address is one that PayPal deems as confirmed.
All Zen Cart does is pass that "parameter" along to PayPal with the transaction. The rest is up to PayPal.
It does not impact any non-PayPal-transactions.

PayPal's explanation: https://www.paypal.com/us/webapps/mp...ddress-outside

Thanks for the helpful link. Does Zen Cart change any processing if PayPal returns an unconfirmed shipping address status instead of confirmed? Or is the result of confirmation by PayPal only displayed on the order details page in admin and stored in the database, leaving the store owner to decide what actions (if any) to take on unconfirmed shipping addresses?

For customers logged into Zen Cart, is the Require Confirmed address parameter set to "yes" and sent to PayPal? Or is "no" sent? Or is the parameter not sent?

For customers not logged in and also for customers logged in, does PayPal return "unconfirmed" to Zen Cart if "no" is sent to PayPal or the parameter is not sent to PayPal?

Thanks, Dave