I figure it's all about intention. If you want/need SRS and are only being stopped by fear/money/whatever, then I would opt for Pre-Op, whereas Non-Op implies to me that you have either no interest in SRS or have decided for whatever reason that it will never happen. I also think this is putting a binary description on something that is more fluid, as you may be Pre-Op one day, Non-Op the next, and completely confused/undecided the day after that.
The only term in this group that really has a discrete determinable definition is Post-Op; either you are or you aren't.