Then, I lived in Tokyo for a few years. People leave belongings unattended in coffee shops and restaurants all the time. It's a common occurrence to see someone put down their belongings at a table, leave them there, then go order food or drinks where their belongings are out of sight.
Sure, there is still theft in Japan. But it was a really eye opening and nice experience to see that there are places where distrust of others in this context isn't the default state.