On the 767, where the auto throttle arm switch lives in the on position, there are other conditions that must be met before pushing the GA bottons will cause GA power to be applied.
On the 767 the two conditions which must be met are glide slope capture or wing flap extension...therefore as we don't extend takeoff flap until after the tug is disconnected and the after start checklist is complete I guess there is no chance we'll end up inside the terminal building.
Surely the 737 has similar protections?