Ye gods. This is not about rape. This is about public drunkenness and indecency, which I presume are crimes under Spanish law. She was drunk and publicly indecent, the men were drunk and/or publicly indecent, and the promoter assisted in the indecency.
Yes folks, believe it or not, the laws of most jurisdictions consider adults responsible enough to be criminally liable for drunkness and acts done while drunk. They also hold responsible those who take advantage of a person's drunkenness, but that is a separate point.
The Spanish authorities may decide she's suffered enough. Or they may decide that she should be prosecuted under Spanish law anyway as she got drunk and committed a sex act on a whole load of blokes out of sheer greed for a holiday.
I wouldn't be surprised if Spanish law doesn't even allow her to sue for her holiday, on the basis that it's an immoral contract.