[jimworcs]

I think your illustration makes the opposite point you are making.

In your analysis, if the second bag costs $25 and the overweight bag costs $90, the airline is profiting from making their employees unsafe by allowing a unsafe weight. Where is the airlines duty of care to their employees? It is utterly unethical to say we will allow our individual employees to become injured and we will use the money we make from the passenger for overweight bags to mitigate the costs. What kind of management is that? They cannot, in the name of customer choice, choose to expose their staff to unnecessary risks.

The truth is, the airlines make ridiculous profits from overweight bags and clearly, based on your analysis, don't give a toot about the consequences for their employees. A more ethical approach would be to simply ban any bag over their chosen maximum weight and tell the passengers they must either purchase another bag and pay for a second bag or the bag can't travel. That would be fair and protect their employees...but far less profitable, so they simply don't do it.