I recently had to pack for a trip on an airline. You used to get three bags at 70 pounds each for free. Those were the glory days. Now you get two bags at 50 pounds, and the airline employees never know their own airline's rules, which still allow bags to be up to 70 pounds. Instead, you have to pull out the airlines rule and show them. Then the agent acts like he is breaking his back, lugging your bag of 70 pounds to the conveyor belt.
Pretty soon, the baggage limit will be down to 17 pounds. Since your bag will weigh 15 pounds, you will be allowed a net 2 pounds of baggage at a cost of $50 per bag.