I completely agree that a bond is more than reasonable, but I disagree that it is anyone other than pilots that set the trend. If nobody was willing to pay for a TR, Airlines would have to provide them, albeit with a subsequent bond. Unfortunately, some people are so desperate to get an airline job, that they will take on even more debt (normally) to pay for a TR themselves.
I find this sad, what next, work for nothing for 12 months? I'd rather stack shelves than be taken advantage of.