HMMM!!!
Never heard of anyone using the driver's side to get into the back seat. The seat doesn't slide when you tilt the seatback forward.
IIRC the passenger seat does not lock forward when you tilt the seatback forward. The seatback does seem to have a slight spring assist when released (but not much). If you are parked uphill, that spring assist may not even be enough to keep the seatback forward while entering. As a matter of fact, when I tilt the passenger seatback forward, I always slide the seat back BEFORE I raise the seatback to it's upright position.
Have you installed seat sliders? If you are using your back seat much, they make a huge difference.