Uhm, actually not. But you can keep the plugin in double opt in mode and remove from the confirmation message the confirmation link, just writing in it that a moderator will activate the subscription after some checks.
An alternative is to let them to activate the subscription but manually assign a private preference and send newsletters only to subscribers with that preference active.
There is no need for this feature since using a private list you can obtain the same result. Let the subscriber confirm his email, so the address is “sure” and then a moderator will add that subscriber, is the case, in a provate list. Then you’ll send your newsletter only on that list.