Enumerations Aren't As Bullet Proof As I Thought

Pass an enumeration as a method parameter and its guaranteed to be valid right?
Wrong!

This code compiles and executes with no runtime error:

using System;

namespace Enumerating_Fun {

 enum EnumLegalColor{red=1, white=2, blue=3};

 class Program {

    static void Main(string[] args) {

       PrintColor(EnumLegalColor.red);
       PrintColor(EnumLegalColor.white);
       PrintColor(EnumLegalColor.blue);

       PrintColor((EnumLegalColor) 1234);
 
       while(!Console.KeyAvailable)
          ;
    }


    static void PrintColor(EnumLegalColor color) {

       switch(color) {
          case EnumLegalColor.red:
             Console.WriteLine("Le Rouge");
             break;
  
          case EnumLegalColor.white:
             Console.WriteLine("Le Blank");
             break;
  
          case EnumLegalColor.blue:
             Console.WriteLine("Le Blu");
             break;
  
          default:
             Console.WriteLine("WTF!");
             break;
       }
    }
 }
}