This is likely not much of an issue at this moment but when applications will really start to believe in that problems will start. Values for various LC_<things> should be carefully reviewed. In particular I noticed that LC_PAPER for en_CA and fr_CA locales claims that A4 paper is used. In reality it is nearly impossible to find in stores and in everyday use anything else but US "letter" format. It would not surprise me if that would be the same all over North, and possibly Central, America and quite a few other places as well (Phillipines, for example?).
Ulrich accepted the changes, so this will be fixed in glibc-2.2.3-14.