If you look at it like that, but pokertracker doesn't factor in bonus, it gives you stats and tells you how you are fairing in the actual game your playing.
Once you leave the micro-stakes the bonus isn't as much of a buffer.
At 1/2, a 50BB loss during bonus clearing (assuming full bonus) still leaves you +$100.
At 3/6, that same 50 BB loss during clearing leaves you down $100.
So, you should've said, "if you guys learned to play micro-stakes (again) and bonus clear, you'd never have a losing session."
Then, I still don't think I'd agree with the basic premise of the statement.
