No, no, no.
While . NET indeed uses the date format set in the Windows settings by default, the intrepid developer can and should set it to whatever they need, especially when their software doesn't have internationalisation. This is not user error, this is a bug, no matter how easy it is to work around it.
Ideally, Steve would set the CultureInfo. CurrentCulture for Aurora to something he expects will fit at all times.
Its actually a more general problem. The same date in the same format is still different lengths in different languages. If I fix the date format in the game, I am preventing people from choosing a suitable date format for their location.
He's saying that you can set the culture so that the date is always in English, and in the en_GB long format, so that the dates are always the expected length. Obviously there is some advantage to presenting the dates in the user's language, even if the rest of the text is not translated, and you would lose that.
The other option, of course, is to give the user a UI for controlling the date format. Letting the user choose between the system long date format, the system short date format, and a custom date format string would cover all the possibilities.
A further option would be to use a table control rather than a list control. The table controls can allow resizing any field, as well as nifty things like sorting by any field when the user clicks on a column header. As a bonus you could then eliminate all of the "sort by X" buttons that you have in some of the windows.