For a long time I thought this was a temporary arrangement while some other construction was completed; it seems to be permanent though.
Personal experiences? As yultraveler writes, you might have to wait for the bus to fill up. If you wait for a long time, then get off the bus and go back inside to use the men's room, you will set off the alarm! Thankfully it is just an alarm; doesn't put the whole terminal in lockdown.

Both guides are correct - the old approach of clearing customs and then reclearing security still works just fine