Road block
If I recall correctly, Tatsumi causes a rockslide to block the road (in the manga, the anime, or both?). Naturally, the villagers clear it after blocking Sotoba's only exit themselves. This is not only ironic, but completely hypocritical. A collapsed road would quickly attract outside attention and be reported—which is why the authorities actually warned the villagers to remove the roadblock during the hunt.
P.S. If I remember correctly, didn't Tatsumi (or someone else) suggest cutting the phone lines too? That seems equally flawed—in a system like Japan's, wouldn't a sudden, total line outage in Sotoba be detected almost instantly from the neighboring town of Mizobe?