[TYPO3-shop] Newsletter with double opt-in?

[Robert Markula]

Hi,
is there a way to implement double opt-in for advertising during the
purchase process?

E.g. a customer wants to buy some items from the online shop. During
checkout, perhaps while entering the delivery address, he can optionally
tick a checkbox if he wants to receive advertising.

The problem is, that in germany it is common jurisdiction that vendors
are required to use double opt-in - which means that the customer would
receive an e-mail in which he has to confirm that he wants to receive
advertising. IMO that's a useful and right procedure, but how to
implement this with tt_products?

Cheers,
Robert