Cops actually find stolen bikes in Japan? Whoa, that is different.
I never expected much---and I sure didn't expect them to find it a year and a half later. Apparently it was left in a no-bike-zone and they realized it was stolen from the registration number. Glad I registered!
OK, I shouldn't have said that because it is an overgeneralization and is overshadowing the point I was trying to make. Coming from New York, I still think people generally don't lock their bikes. They certainly don't chain them to posts with 1/2" steel chains. There is definitely still theft and crime though.
The point that crime like theft is lower in Japan is totally valid, but I can promise you people do lock their bikes---bike theft is very common. You might not have noticed it because most bike locks come built into the bikes themselves. I don't think I've ever seen those kinds of locks in North America.
Furthermore, anyone who has a mountain bike or crossbike does chain them to posts with 1/2" steel chains. The far more common "mama-chari" type bikes are the ones with the built-in locks.
I've had three bikes stolen since I first came here in 1998---one of them twice! The cops found one of my bikes a year and a half after it was stolen. Within six months it was stolen again!