Leafy, I am not disputing the right of an operator to bond pilots for reasonable training costs. But I fail to see the ethics of charging salaries when pilots being trained or conducting training are on revenue-producing operations - as are training captains and trainees during the line training phase. The non-revenue costly bit ends at simulator or aircraft base check.
The only additional costs could be the captain's training allowance - though that is really a fixed overhead regardless, because CASA require a certain ratio of training captains to line pilots - and is usually offset by the trainee being on probation pay rate until checked to line.
I absolutely agree that pilots should serve their bond out, or pay a penalty for an early exit, but terms need to be fair.