When my car trips, I like to throw flicks Wave to check that all is well behind (I see you coming, it is not more dangerous than to control the middle retro!). My son is installed back on the road, on a side instead. I put this mirror on the headrest of the middle seat (do not have three people in the back, I grant you, but it is easily removed.) I clipped the strap and pulls it for all tighten. I rule by turning the car seat, very easily and that's it.
I still asked the question of the behavior of this mirror during a crash test ... mystery.