diff --git a/lib/MemberBuilder.js b/lib/MemberBuilder.js
index 20f032a..1719a86 100644
--- a/lib/MemberBuilder.js
+++ b/lib/MemberBuilder.js
@@ -438,6 +438,12 @@ function hideMethod( super_method, new_method, instCallback, cid )
     // TODO: This function is currently unimplemented. It exists at present to
     // provide a placeholder and ensure that the override keyword is required to
     // override a parent method.
+    //
+    // We should never get to this point if the default validation rule set is
+    // used to prevent omission of the 'override' keyword.
+    throw Error(
+        'Method hiding not yet implemented (we should never get here; bug).'
+    );
 }
 
 
diff --git a/lib/MemberBuilderValidator.js b/lib/MemberBuilderValidator.js
index 1932b50..b18cfbc 100644
--- a/lib/MemberBuilderValidator.js
+++ b/lib/MemberBuilderValidator.js
@@ -142,20 +142,15 @@ exports.prototype.validateMethod = function(
             );
         }
 
-        // if redefining a method that has already been implemented in the
-        // supertype, the default behavior is to "hide" the method of the
-        // supertype, unless otherwise specified
-        //
-        // IMPORTANT: do this last, to ensure we throw errors before warnings
-        if ( !( keywords[ 'override' ] )
+        // Disallow overriding method without override keyword (unless parent
+        // method is abstract). In the future, this will provide a warning to
+        // default to method hiding.
+        if ( !( keywords[ 'override' ] || prev_keywords[ 'abstract' ] ) )
         {
-            if ( !( prev_keywords[ 'abstract' ] ) )
-            {
-                throw Warning( Error(
-                    "Hiding method '" + name + "'; " +
-                    "use 'new' if intended, or 'override' to override instead"
-                ) );
-            }
+            throw TypeError(
+                "Attempting to override method '" + name +
+                "' without 'override' keyword"
+            );
         }
     }
 };
diff --git a/test/MemberBuilderValidator/MethodTest.js b/test/MemberBuilderValidator/MethodTest.js
index d4413a7..e58551b 100644
--- a/test/MemberBuilderValidator/MethodTest.js
+++ b/test/MemberBuilderValidator/MethodTest.js
@@ -34,10 +34,15 @@ require( 'common' ).testCase(
          * Tests to ensure that a method with the given keywords fails
          * validation with an error message partially matching the provided
          * identifier
+         *
+         * To test overrides, specify keywords for 'prev'. To test for success
+         * instead of failure, set identifier to null.
          */
-        this.quickKeywordMethodTest = function( keywords, identifier )
+        this.quickKeywordMethodTest = function( keywords, identifier, prev )
         {
             var keyword_obj = {},
+                prev_obj    = {},
+                prev_data   = {},
                 name        = 'fooBar';
 
             // convert our convenient array into a keyword obj
@@ -46,12 +51,34 @@ require( 'common' ).testCase(
                 keyword_obj[ keywords[ i ] ] = true;
             }
 
-            _self.quickFailureTest( name, identifier, function()
+            // if prev keywords were given, do the same thing with those to
+            // generate our keyword obj
+            if ( prev !== undefined )
+            {
+                for ( var i = 0, len = prev.length; i < len; i++ )
+                {
+                    prev_obj[ prev[ i ] ] = true;
+                }
+
+                // define a dummy previous method value
+                prev_data = { member: function() {} };
+            }
+
+            var testfunc = function()
             {
                 _self.sut.validateMethod(
-                    name, function() {}, keyword_obj, {}, {}
+                    name, function() {}, keyword_obj, prev_data, prev_obj
                 );
-            } );
+            };
+
+            if ( identifier )
+            {
+                _self.quickFailureTest( name, identifier, testfunc );
+            }
+            else
+            {
+                _self.assertDoesNotThrow( testfunc, Error );
+            }
         };
 
 
@@ -343,5 +370,30 @@ require( 'common' ).testCase(
             this.quickVisChangeTest( cur[ 0 ], cur[ 1 ], false );
         }
     },
+
+
+    /**
+     * If a parent method is defined and the 'override' keyword is not provided,
+     * regardless of whether or not it is declared as virtual, we need to
+     * provide an error.
+     *
+     * Note: In the future, this will be replaced with the method hiding
+     * implementation.
+     */
+    'Must provide "override" keyword when overriding methods': function()
+    {
+        this.quickKeywordMethodTest( [], 'override', [] );
+    },
+
+
+    /**
+     * Building off of the previous test - we should be able to omit the
+     * 'override' keyword if we are providing a concrete method for an abstract
+     * method. In terms of ease.js, this is still "overriding".
+     */
+    'Can provide abstract method impl. without override keyword': function()
+    {
+        this.quickKeywordMethodTest( [], null, [ 'abstract' ] );
+    },
 } );
 
diff --git a/test/test-member_builder-method-hiding.js b/test/test-member_builder-method-hiding.js
index eb6c4a7..e96448f 100644
--- a/test/test-member_builder-method-hiding.js
+++ b/test/test-member_builder-method-hiding.js
@@ -41,6 +41,9 @@ var common  = require( './common' ),
     )
 ;
 
+// XXX: Disabled until we begin re-development of this feature
+return;
+
 
 /**
  * Restores warning handler to the default