Currently there are no additional steps when editing activity that is live than one that is inactive. In this way any edits to a live test are set to live by saving the changes. At the same time there is no indication that this is a live test while on the edit screen. Both combine to a high risk of introducing updates directly to a live test.
I would recommend two updates. First, all edits get reviewed before set to active. In the case of experiences that are already live the best action would be to have any update to an activity move the experience back to inactive along with a prompt explaining the move. This allows an opportunity for review updates before setting those live. Second, include the status of an experience in all edit screens. This will allow for a visual indication on if this test is currently either active or inactive.