Why don't D&D devils, make deals with kids?

[Psyren]

This is actually the information I go off of with infernal contract disputes. Except with children, I also added "incapable of understanding the contract, because they haven't reached the Age of Reason". The interesting thing is, is that devils will often times make these bad contracts that can be disputed, and the contract is still valid unless the person actually knows they can dispute the contract. So your typical soul might be able to fight their predicament when they hit the shores of Despond, but still get harvested because they don't know their rights. And the devils aren't obligated to tell you.

Are you talking about them making bad contracts in your setting, or are there canonical examples from the rulebooks? Genuine question as I haven't seen the latter.

Traditionally, children were property. You would need the father's agreement.

Putting aside the humor, and that this sociopolitical concept of property is unlikely to extend to metaphysical realms, this strikes me more generally as another example of where the "medieval flavor" of D&D's setting doesn't perfectly translate to the game as a whole - much like women being allowed to adventure or a large number of people outside the clergy being literate.