My system locale is ru_RU.UTF8. Today wjile writing a CD I've successfully typed in name (label) field "Концерт Мосальск 08.05.2013" (containing localized, i.e. Russian symbols), find no warnings in burn dialog, burned CD. And only on test mount find, that disk label was splitted to "Концерт Мосальск". Later performed check showed no field size limitations or check. The best solution of this issue to my mind will be add a field size limitation according to standard's size limitation (English char == one byte) and extended char/byte check (by default xfburn fits this field with Russian, Cyrillic chars, which are encoded by two bytes) before opening burn dialog.
Closing old bugs.