Testing for Endianess

A colleague is studying for a Microsoft Interview.
One of the questions is to write code to test for Endian.
The answer Microsoft likes involves bit twiddling, but one wonders why they would not prefer calling their own framework:
using System;


using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace ConsoleApplication1

{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("BitConverter.IsLittleEndian " + BitConverter.IsLittleEndian.ToString());
Console.ReadLine();
}
}
}