2) carseats have their own set of internal restraints, so if someone were to tug on the child the whole seat would come too.
The main thing for people with kids is convenience (and courtesy for those who care about such things). If the rig folds into something more compact that can be stowed, it's a lot more convenient (and courteous) than the check-at-the-gate Mercedes-Benz-size stroller.
The analogy of the computer program is similar to evolutionary psychology's ESS: evolutionary stable strategy. While strategies can evolve by chance, successful ones are combinations that are stable -- that is to say that resist exploitation by mutants. Most work by cooperating with individuals like themselves and competing with individuals unlike themselves.
The analogy is pretty good, as far as it goes. It does tend to pit demographic cohorts against one another, and makes no allowance for social or philosophical progress.
