12ShotTwo, is right on. Extra insurance is available but finding a ticket agent who knows how to do it is going to take some time! You might want to save the paper work from the outgoing trip to show the ticket agent on the return flight how to do it.
I made the Vegas Mid-Winter shoot for a number of years. After the first couple trips I just took my cheap gun to save the hassle from buying insurance. Worked out okay, I've got all my wins and yardage with the cheap gun. And one year in Vegas I actually paid for airline and hotel with shoot winnings, shooting the cheap gun! LOL