All the characters in my example are printable. Not all of the octets are, of course, but octets aren't characters. And spaces are extremely common in names, e.

All the characters in my example are printable. Not all of the octets are, of course, but octets aren't characters. And spaces are extremely common in names, e.g. music track and album names contain spaces more often than not (and thus usually end up in file names). If you can't even support using the biggest key on every keyboard in file names you're doing something horribly wrong.