alt Hacker NewsThey're legally required in a lot of countries on small kids bikes and not easy to disable. I think the argument is that kids lack the strength to operate a hand brake effectively. Experts all seem to say that coaster brakes are terrible for safety and learning though.
Hand strength is an issue with cheap, adult sized cable hand brakes but not an issue with smaller levers or even the cheapest hydraulic brakes.
The kids bikes that require them ate also made of mild steel and with more than my Enduro bike.
Don't buy a cheap, department store kids bike. You can get multiple kids through a quality bike and still sell it for like $100 less than you paid.