The coaster brake wheel will just slide. A front wheel with a hand brake has more effective braking action due to simple physics....it's called inertial transfer of weight. The other aspect is that it's better braking with 2 wheels than just one.
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. “He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you.”- Fredrick Nietzsche
"We can judge the heart of a man by his treatment of animals." - Immanuel Kant