For my sister's wedding, she will need to get her dress from Omaha to Chicago. She got it at David's Bridal so they already told us they can do a complimentary steam when it arrives because I'm sure it'll be a bit rumpled, but she wanted to figure out the way that would be gentlest on the dress.
She was told that a lot of people FedEx/UPS the dress, and just use a garment bag for protection and have the package labeled as fragile. And of course get insurance on it. But if something did happen to it, the insurance is nice but she's more worried about the panic at the last minute moreso than being compensated if it gets destroyed.
Is shipping the dress a bad idea though? It does leave a lot to chance ... her other option would be taking it with her when she flies up there but she wasn't too keen on wrestling with a big gown through the airport. But it may come to that just for peace of mind, especially if shipping isn't recommended.