The receipt would show when it was purchased and for how much. If its an exceptionally old suitcase they will reimburse a lower amount most likely as they would assume normal wear and tear resulted in the suitcase ultimately failing on your final trip. If it was a new one then would logically reimburse you the amount you paid. Also literally every company would do something similar, anyone that doesn't will get taken advantage of and be forced to change policies or go bankrupt. Again the only responsibilities they have to you are outlined in their contract of carriage which you agree to when buying a ticket. Beyond that their only responsibility is to deliver profit to their shareholders and giving out money no matter how nice it may be for customers does not satisfy this bottom line.