Hi.
I created the module. 1.5 hours of work. It checks the email and also the delivery address. So it adds a gift to only one email, be it a guest or a customer. If a different email is entered, but the address is the same, the gift will not be added. If the customer selects "Reorder", the gift product will not be added from the previous order.
It will be tomorrow @sampsonzak test.
After that, this thread will be marked as resolved.