My client used A/B testing for emails a few times. People then were spammed with 2 emails each time when the "winning" version was sent out to the "losing" test people when the test completed. This caused numerous complaints, unsubs, etc. The client's sister even called asking why she was getting spammed. This is definitely undesired behavior and should be a simple option - similar to the "resend to unopened" option, it should be "send winning email to the alt-test recipients" and toggled on or off depending on the user's wish.