Hatchback/liftgate Lock problems of the 2004 Toyota Prius

In the 2004 Toyota Prius there is a button on both back seats by the headrests that unlatches the seatback. My four year old can easily push down this button with one finger, and my concern is that a child (or others) could unlatch the seat without the driver knowing. Should the car crash or stop suddenly the seat could come down, possibly with a passenger in it. I told the car dealer and a Toyota customer service rep about my concern. I was told the button is not designed that way, but when I contacted a second dealership their 2004 Prius did the same as the car I tested. I was told that it was designed so that you had to continue to hold down the button in order to pull the seatback forward. This is not the case in reality. The button needs to be childproofed either by moving it so it is not easily seen and reached by a child, providing a cover, or adding a light on the dash so the driver is aware of the seat being unlatched. I was told that it was also designed so that the seat could not be unlatched while the car was in motion. Also not true. I was the first to notice this unsafe feature, and we were in motion when I unlatched my seat.