I won't turn it off until I do an update where I force everyone to restart. Remember, there are people jumping back into old saves from over a year ago. I believe we had an example of that just a few pages ago.I think it would be OK, since it will only define the variable if it doesn't already exist, but I understand your reluctance to mess around with working stuff when you don't have the time/saves to do adequate testing.
Maybe you could stop the rollback blocking on future updates, since you're using default now? Turn it off at the first part of the new code, or don't turn it on if past a certain point in the story.