Ok, from the Apple developer docs it seems you do have to let the user do something to make the restore. It says
“… if your application supports product types that must be restorable, you must include an interface that allows users to restore
these purchases. This interface allows a user to add the product to other devices or, if the original device was wiped, to restore the
transaction on the original device.”
I guess I will add a restore function (button), and not do it automatically.