Actually I do.
Every sim or line flight under "training" is graded. If you are doing an upgrade, 3 failures(2 or less)at any point during the course and you are back to being an FO.
Therefore, even a LOS, which should be considered as training, carries risk. You will also carry any "failure" with you throughout the course. So, get a 2 during LOS 1, you will redo the entire LOS. Get a another 2 during LOS 2, you will redo the entire LOS. Fast forward 3 months to your line release check, make a mistake which the TRE does not like, you're an FO.
It is that simple. Every training event is graded and carries risk!