Airlines currently charge surcharges for special seats. This prevents a family from sitting together unless they want to pay the extra fees.
When there is availability at the time of ticket purchase, seats that are purchased together should be allowed to be selected together as well. It is obscene that a parents should be held hostage by fees to be able to sit next to their child or required to negotiate with strangers to trade. In a time when we are punishing parents for leaving their children alone in cars, it is shocking that it is acceptable to place them next to perfect strangers or pay hefty fees.