Usually, we don't use japanese for setting to computer. Because, japaese needs at least two byte. Usually, many computer systems are designed for one byte. So, to use japanese in the system setting was not common way. If he is usual engineer then he will not set japanese for the setting to SSID. I was not do such a thing.
Today, i read a tweet written by my friend. He wrote that he could see the japanese ssid from his house. I was really suprized when i read it. So, I asked prof. Google about this ssid expression in japanese. So, it is exist.
Now, I had no wireless devces for trying it. But,it is so intersting thing for me.