Default status for manually added Subscribers

If we add new subscribers on the admin page all of them are set to confirmed by default, even tough double opt in is enabled. If a client subscribes via the frontend form everything is ok and the confirm mail is sent.

Is it possible to set de default status for self added subscribers so they get the confirm mail as well? Either by a setting or a filter I can hook in?

I think a filter for the $data array would be also useful in other use cases.