Southwest once made me check an umbrella stroller at the gate, after the desk personnel assured me that the flight attendants would store it on the plan. Stroller did not make the flight, they did however get it back to me about three days later.
As for cruise lines, the only luggage mishap that we have had (knock on wood) is we left a bag in New Orleans at the dock. Called Carnival the next business day after we got home to let them know that we had left the bag. They found the bag and sent UPS to our home. We had to pay the shipping but at least I got the bag of dirty laundry.