Not sure it is a real issue in that you still have a full hour to return for your BG. The BG just start's boarding at the time. For example no BGs had started by 8:30 AM today.Your BG was called at 8:30. . .1/2 hour before the park opened? For those of us struggling to make it there by rope drop (i.e. Skyliner etc), that's really not cool.
It really depends on the attractions startup for the day and how it decides to operate on any given day of operations.
Dave