Share on Facebook Share on Twitter Share on Google+ Share on Reddit Share on Pinterest Share on Linkedin Share on Tumblr So far, this year’s Microsoft CEO Summit has been all about Canadian Prime Minister Justin Trudeau’s talk today, but there’s been precious little information available about who else is attending – and Trudeau may be one of the big reasons why. Microsoft co-founder Bill Gates created the annual summit back in 1997, to give global business leaders an opportunity to share their experiences and learn about new technologies that will have an impact on business in the future. The event’s attendee list is kept largely confidential, as is the substance of the discussions. This year, Microsoft says the summit’s two themes are “trust in technology” (as in cybersecurity, international hacking, privacy and the flow of data) and “the race to space” (as in privately funded space efforts such as Amazon billionaire Jeff Bezos’ Blue Origin rocket venture). Usually, Microsoft lists a few folks who are attending the summit on the company’s Redmond campus, just to give a sense of the event’s cachet. For example, last year’s headliners included Berkshire Hathaway CEO Warren Buffett and Exxon Mobil CEO Rex Tillerson (who is now the Trump administration’s secretary of state) This year, however, the spotlight has fallen almost exclusively on the hunky 45-year-old Trudeau, the first sitting head of government or state to address the summit. Microsoft isn’t saying anything about the other 140-plus VIPs attending the discussions. “Out of respect for the privacy of our guests, we are not providing any additional information,” a Microsoft spokesperson told GeekWire via email. Even Trudeau’s remarks at the summit are hush-hush, although officials say he’s talking up Canada’s tech sector. The best opportunity for public exposure comes on Thursday, when he’ll have a photo op with Washington Gov. Jay Inslee in downtown Seattle. Trudeau and Inslee will then talk amongst themselves about regional issues such as high-tech collaboration and high-speed rail systems. In the old days, journalists could suss out information about attendees from pictures, or from summaries of remarks that Microsoft made available. In 2008, a Seattle Times reporter was famously able to get a sense of which companies were represented by checking the tail-number registrations for planes arriving at Seattle’s Boeing Field. So Boeing Field KBFI is hopping with Business Jets today in Seattle #bizav pic.twitter.com/rzsTOKoVGX — Isaac ✈ Alexander (@jetcitystar) May 17, 2017 But as the years have passed, CEOs and their companies have gotten smarter about evading the paparazzi. Those tail numbers are a case in point: It’s gotten much harder to tell who’s riding in which private jets, in part because executive jet service has turned into such a commodity. For example, more than a dozen NetJets flew into Boeing Field on Tuesday alone, but you can’t tell who paid the fare. Other companies arrange for holding companies to take on the ownership and operation of their jets, or have their flight records removed from publicly available databases such as FlightAware and FlightRadar24. That’s the case for the private jets used by Microsoft co-founder Paul Allen (operated by Vulcan Aircraft Corp.) and SpaceX founder Elon Musk (operated by Falcon Landing LLC). So what’s left? Planespotters occasionally can track down the registration numbers they see at local airfields. For example, one of the planes sighted at Boeing Field is owned by PayPal, even though it can’t be tracked on FlightAware. And this week, China-based Deer Jet publicized the arrival of a 787 Dreamliner business jet that brought Adam Tan Xiangdong, the CEO of China’s HNA Group, to Seattle. It’s a safe bet that Tan is among the VIPs at Microsoft today. There’s at least one other person letting folks know on Twitter that he’s at the summit. That would be Judson Althoff, executive vice president of Microsoft’s Worldwide Commercial Business. Excited to welcome #CEOs from all over the world to #Microsoft campus for CEO Summit 2017 pic.twitter.com/dOUH91Hvqf — Judson Althoff (@judsonalthoff) May 17, 2017 GeekWire’s Chelsey Ballarte contributed to this report.