I probably wouldn't, but that age is such a distant reality right now, I might be imagining a 12 year old body with a little 3 year old inside because that's the age I'm in right now.
I will say though that for me, I imagine it'd be less about me trusting my children, and more about me NOT trusting other people. Sad as that may be. I do agree though that a lot depends on the kids - if the younger would listen to the older and the older was mature enough, I might consider it.