OK. You guys have got me on the 14mm socket thing. Never saw that coming! But now explain this:
I have two little kids. In all of the cars I have owned in the last 20 years except one, there were seat belts for three passengers in the back. The receiver for the center seat belt and a side one were adjacent and visually nearly indistinguishable, but not interchangeable. The inconvenience of having to get the belt around a child seat and blindly find the seat belt receiver is in itself a chore. Getting it wrong on the first try and having to fish for the other one is just punishment. There is absolutely no reason for a bias. The receivers mount right next to each other, and can easily be overlapped during use. Explain this one to me.