Rich guys in Florida, to be precise.
Supercar brands do stuff like this regularly, and the routine appears to be spreading to other premium, though not necessarily supercar, companies. According to a report on the Bimmerpost forum, the all-new 2016 7 Series is being revealed sometime today, April 15, in Coral Gables, Florida. It is a private viewing event. No press will be allowed. Those invited will have to check-in their smartphones and cameras before entering.
In the words of the official invite, this is "the first time in the history of BMW of North America, we are unveiling an all-new BMW to a select audience prior to the public introduction." A few other teaser images were also revealed, but we're expecting a full, and this time public, reveal in the very near future, perhaps as early as next week.