Just a reminder BTW that since version 2.0 (1996), Unicode is not an encoding scheme but a character set (I avoid the confusing “charset” word on purpose). Therefore, Unicode does not use any number of bytes: it only assigns code points to characters.
Windows used to use the UCS-2 encoding scheme which indeed used 2 bytes for each character, but since Windows 2000, it uses UTF-16 instead, which like UTF-8 uses a variable number of bytes per character.
Even with UTF-16 that quote is incorrect, due to surrogate pairs. It's only correct for UCS-2, and even then, only if you take 'characters' to mean 'codepoints', and take 'Unicode' to mean 'a specific Unicode encoding'.
But you're programming "with Ubuntu", not Windows. IMHO you could safely assume/recommend UTF-8.