So the plan is to wait until December 18th to select a location, then blitz advertising in 3 days to get a million people to attend.
Genius.
Because all these artists and their managers, plus the sound and lighting suppliers and operators, plus the DJs, plus the suppliers of food, water and toilets are all going to commit without even knowing the location of the venue. Especially for an event which is scheduled for a few days before Christmas. Because it's not likely anyone needs to organise transport, accommodation or moving their gear.