You cannot. I'm certain Google does not want that possibility. There's no doubt that it could be horribly abused. I can see people sneaking onto a friend's/sibling's/whoever's account and changing that setting without the person knowing. That could potentially lead to a great deal of embarrassment.

I suppose they could set up some checks or something, like have it send you a text message when the setting was changed, but I think Google would like to avoid any chance of the potential fiasco that could lead to.