http://en.wikipedia.org/wiki/Japanese_superstitions#Death_and_the_supernaturalWould 4 being some "unlucky number" in Japan really be enough not to use it for PS4?
There are several unlucky numbers in Japanese. Traditionally, 4 and 9 are unlucky. Four is sometimes pronounced shi, which is also the word for death.[3] Nine is also sometimes pronounced ku, which can mean suffering. 13 is also occasionally thought of as unlucky, although this is imported from Western culture. Because of these unlucky numbers, sometimes levels or rooms with 4 or 9 in them don't exist in hospitals or hotels, and particularly in the maternity section of a hospital, the room number 43 is avoided because it can literally mean "still birth." Therefore, when giving gifts such as sets of plates, they are normally sets of three or five, never four.[2]
I don't know about CE products, but I have heard of their superstitions before in buildings and stuff. Similar to western buildings avoiding a thirteenth 13. I guess it's more the association then the similarity, so Japan won't shun 4 entirely (good like getting anywhere with your culture if you just ignore the number 4! Why even name them the same name?!) but in a hospital you don't want people reading 'death' everywhere! As such, I can see Sony wanting to skip PS4 in Japan if it also reads PlayStation Death. Really dumb name choices for numbers - why don't they just pick new names for 4 and 9 and solve all this nonsense?