Added some additional comments on open_bang

core/common/src/main/scala/net/liftweb/common/Box.scala

@@ -209,14 +209,19 @@ sealed abstract class Box[+A] extends Product with Serializable{
   /**
    * Return the value contained in this Box if it is Full;
    * throw an exception otherwise.
+   *
+   * Using open_! in an example posted to the Lift mailing list
+   * may disqualify you for a helpful response.
+   *
    * The method has a '!' in its name.  This means "don't use it unless
    * you are 100% sure that the Box is Full and you should probably
-   * comment your code with the explanation of the guaranty.
+   * comment your code with the explanation of the guaranty."
    * The better case for extracting the value out of a Box can
    * be found at http://lift.la/scala-option-lift-box-and-how-to-make-your-co
    *
    * @return the value contained in this Box if it is full; throw an exception otherwise
    */
+  @deprecated("Don't use this method unless you are guaranteed of a Full Box", "2.4")
   def open_! : A
 
   /**