I'm not with DJ so I may be off the mark here.
At QF, the ground staff or CSM will check with the Captain or F/O if they can commence boarding. It appears that DJ is considering moving to a system whereby they will commence boarding without that check and if something happens that will prevent boarding at the appropriate time then it's up to the crew to let the ground staff know.
.I heard they may want to start using fwd door only
Watch your OTP suffer when that first comes in. DJ loads a 737 heaps more quickly than QF by reducing the numbers of bottle knecks caused (probably by half) by having the rear door available.