Ludicrous, selfish behavior by her.
Similar thing happened to my DP, his best friend called of a wedding at v short notice, but that was due to relationship breakdown. Luckily for the guests, it was to be held locally, but 8 guys had arranged to go to Las Vegas for the stag, was non refundable.
Anyhow, my DP was best man and it was a tough time for him, but the guys went to Vegas anyway (minus cold footed groom) and had a blast.
To me, the moral of the story is that while a) its always better to call off a wedding than to go through with it for the sake of politeness, its also b) daft and selfish to expect others to make expensive and inconvenient travel plans on your behalf.
In this case, my heart was breaking for the bride, and I also felt sorry for the groom. But as my DP had to sort out so much of the fallout, I also thought why did you muppets not just stay living together until you were absolutely sure.