I agree. And window locks operable by the tenant would be a good idea.
Ensure the windows work properly (ie both halves of the sash open), then the parents can control which bit's open. Any open window can be a danger if the child is very inquisitive - the parents have to be responsible and not leave the kid alone in a room with open windows if there's any danger of them falling out, or fit window bars etc.
'Pause you who read this, and think for a moment of the long chain of iron or gold, of thorns or flowers, that would never have bound you, but for the formation fo the first link on one memorable day'. Charles Dickens, Great Expectations