The Prime Minister's wife at a rave, what is the world coming to? But the clues were there to see. It was an "international music summit", set in a Unesco World Heritage Site and it ended at midnight – not exactly hardcore.
One youngster at the IMS Grand Finale Festival revealed that at least 10 per cent of the crowd were old... well, over 30.
As her husband was wrapping up world affairs at the G8 summit, Samantha Cameron, 40, opted to join friends, along with 2,000 music fans, at the IMS Grand Finale Festival set in Ibiza's Dalt Vila fortified old city.
The appearance of a woman, who only a few days earlier had been hosting US President Barack Obama and his wife Michelle, caused a stir. "Just spotted Samantha Cameron...funny to see her amongst lots of young ravers!" tweeted MrsDebbieC.
Some papers proclaimed: "PM's wife Samantha Cameron parties at 'druggy' Ibiza rave", while others were swift to recall her university friendship with rap star Tricky.
But yesterday those who attended the IMS event seemed distinctly nonplussed about the fact the PM's wife was present, apparently looking "relaxed and happy", enjoying a quiet drink in the VIP area.
The Prime Minister and his wife are spending the half-term holiday on the Spanish island with their children Florence, Nancy and Arthur.
"I am not surprised she was there at all," said one music lover. "IMS is really grown-up – it is all about getting back to basics, about the music. They are not interested in pissing the government off, not interested in having a rave."
The event, which started as early as 6pm, was actually the finale of a three-day conference of panels, discussions, debates and interviews with key industry players in the electronic dance music world. Headlining were 2ManyDJs supported by Dubfire, Radio One DJ Pete Tong (co founder of IMS) and Jason Bentley with some live performances from Hercules & Love Affair and The Japanese Popstars.
Some conceded that there were drugs at the event, while others pointed out: "Maybe there were drug users but no more than you would see in the average Wall Street office."
Juriel Zeligman, a brand manager at the Ibizan music collective Finca AM, said: "People are so narrow minded because there were electronic DJs playing. If it had been a jazz band, the newspapers wouldn't have written about it.
"A rave has so many negative associations but there were also a lot of professionals meeting to do business. The idea was to have a good time and make deals with big brands from the conference.
"Back stage there was a gathering of professionals and out front people could buy tickets for €25 (£22) and have a good time. There was not one incident or one fight. People were just smiling and having fun," Mr Zeligman said. "It stopped at midnight and then people could go on and rave at the clubs."
Many people headed to Pacha where Tong ended the night, signalling his return to the famous club with the launch of "Pure Pacha All Gone Pete Tong".
While security was tight, it was low-key, said those attending the event, insisting there was music to appeal to a younger crowd as well as long-standing festival favourites.
Another party-goer added: "Rob da Bank (the DJ and record label owner) was there with his kids (sons Arlo 4 and Merlin 2). If it was hard core, he wouldn't be there with his kids. It was chilled, not massively ravey, more like an evening at a festival when it is winding up. It ended early on purpose to keep the (local) government happy – strike a deal that it would be civilised. It ended at midnight before it could get messy."
The Balearic island, which has been ravaged by forest fires in the past few days, developed a reputation for ecstasy-induced raves in the late Eighties and Nineties with super clubs competing to offer increasingly outrageous entertainment.
The local government, keen to promote a more family-friendly image, has clamped down on much of the wilder behaviour. Attempting to attract a more cultured, international crowd, it has passed a series of new measures such as requiring clubs to close by 6am, banning parties and encouraging more luxury hotels.
However, locals said that it had softened its stance this year and was trying to work with the club scene now, appreciating how much business it brought in. The efforts seemed to have paid off with Ibiza increasingly popular with wealthier holiday makers, such as the Camerons, who opt for the rocky coves and fashionable hotels scattered around the North of the Island, far from the party scenes of San Antonio and Ibiza Town.
But rave fans insist the music scene is as vibrant as ever, attracting top DJs and artists over the summer.