Function for correcting capitalization of user-entered names

NameCase.cs

namespace NeoSmart
{
    public static class Utils
    {
        //This function will only attempt to capitalize the first letter, etc. of a name
        //if and only if the user appears to have entered all caps or all lowercase
        public static string ProperCase(string stringToFormat)
        {
            System.Globalization.CultureInfo cultureInfo = System.Threading.Thread.CurrentThread.CurrentCulture;
            System.Globalization.TextInfo textInfo = cultureInfo.TextInfo;

            //Check if we have a string to format
            if (String.IsNullOrEmpty(stringToFormat))
            {
                //Return an empty string
                return string.Empty;
            }

            //Check if string already contains both upper and lower, in which case assume it's correct
            bool hasLower = false;
            bool hasUpper = false;
            foreach (char c in stringToFormat)
            {
                if (!Char.IsLetter(c))
                    continue;

                if (Char.IsUpper(c))
                    hasUpper = true;
                else
                    hasLower = true;

                if (hasUpper && hasLower)
                    return stringToFormat;
            }

            //From http://msdn.microsoft.com/en-us/library/system.globalization.textinfo.totitlecase.aspx:
            //"However, this method does not currently provide proper casing to convert a word that is entirely uppercase, such as an acronym."
            return textInfo.ToTitleCase(stringToFormat.ToLower());
        }
    }
}