Pretty sure you can take the airport express and then go downstairs into arrivals without a boarding pass.
They screen everyone now! But I only needed a flight confirmation with my name on it, email was fine.
Just create a fake ticket using Return Flight Tickets - Print your own flight ticket
There are plenty of services like this. The above one is free, some others charge around US$5 per ticket and have more options for choosing different airlines, etc.
People all over the world create fake tickets like this all the time. The most common need for this is if you travel on a one way ticket somewhere and the stupid airline doesnt let you board without a return ticket because you are not resident at the destination, then just create a fake ticket. Very useful for backpackers and people that don't plan their schedules so far ahead. The airlines are morons for creating this underground fake ticket industry.
HK airport is just as moronic but the same stupid solution to exists to get around the stupid problem.