diff --git a/config/flay.yml b/config/flay.yml
index 48be7fe8..884cf67e 100644
--- a/config/flay.yml
+++ b/config/flay.yml
@@ -1,3 +1,3 @@
 ---
 threshold: 18
-total_score: 1132
+total_score: 1114
diff --git a/lib/mutant.rb b/lib/mutant.rb
index 6b7a3eb8..c0902194 100644
--- a/lib/mutant.rb
+++ b/lib/mutant.rb
@@ -103,7 +103,6 @@ require 'mutant/ast/meta'
 require 'mutant/cache'
 require 'mutant/delegator'
 require 'mutant/warning_filter'
-require 'mutant/warning_expectation'
 require 'mutant/require_highjack'
 require 'mutant/isolation'
 require 'mutant/mutator'
diff --git a/lib/mutant/subject/method/instance.rb b/lib/mutant/subject/method/instance.rb
index e05ec8b0..3f5f341f 100644
--- a/lib/mutant/subject/method/instance.rb
+++ b/lib/mutant/subject/method/instance.rb
@@ -7,10 +7,6 @@ module Mutant
         NAME_INDEX = 0
         SYMBOL     = '#'.freeze
 
-        # A list of methods that will warn when they are undefined
-        WARN_METHODS_UNDEFINED =
-          RUBY_ENGINE.eql?('ruby') ? [:initialize, :__send__, :object_id].freeze : EMPTY_ARRAY
-
         # Test if method is public
         #
         # @return [Boolean]
@@ -22,8 +18,6 @@ module Mutant
         end
         memoize :public?
 
-        LINE_INCREMENT = defined?(Zombie) ? -11 : 5
-
         # Prepare subject for mutation insertion
         #
         # @return [self]
@@ -31,15 +25,7 @@ module Mutant
         # @api private
         #
         def prepare
-          expected_warnings =
-            if WARN_METHODS_UNDEFINED.include?(name)
-              ["#{__FILE__}:#{__LINE__ + LINE_INCREMENT}: warning: undefining `#{name}' may cause serious problems\n"]
-            else
-              EMPTY_ARRAY
-            end
-          WarningExpectation.new(expected_warnings).execute do
-            scope.send(:undef_method, name)
-          end
+          scope.send(:undef_method, name)
           self
         end
 
diff --git a/lib/mutant/warning_expectation.rb b/lib/mutant/warning_expectation.rb
deleted file mode 100644
index 71cfbe3c..00000000
--- a/lib/mutant/warning_expectation.rb
+++ /dev/null
@@ -1,47 +0,0 @@
-module Mutant
-  # A class to expect some warning message raising on absence of unexpected warnings
-  class WarningExpectation
-    include Adamantium::Flat, Concord.new(:expected)
-
-    # Error raised on expectation miss
-    class ExpectationError < RuntimeError
-      include Concord.new(:unexpected, :expected)
-
-      # Return exception message
-      #
-      # @return [String]
-      #
-      # @api private
-      #
-      def message
-        "Unexpected warnings: #{unexpected.inspect}, expected: #{expected.inspect}"
-      end
-    end
-
-    # Execute blocks with warning expectations
-    #
-    # @return [self]
-    #
-    # @api private
-    #
-    def execute(&block)
-      warnings = WarningFilter.use do
-        block.call
-      end
-
-      missing    = expected - warnings
-      unexpected = warnings - expected
-
-      if unexpected.any?
-        fail ExpectationError.new(unexpected, expected)
-      end
-
-      if missing.any?
-        $stderr.puts("Expected but missing warnings: #{missing}")
-      end
-
-      self
-    end
-
-  end # WarningExpectation
-end # Mutant
diff --git a/spec/unit/mutant/subject/method/instance_spec.rb b/spec/unit/mutant/subject/method/instance_spec.rb
index 544113d7..2d6c0882 100644
--- a/spec/unit/mutant/subject/method/instance_spec.rb
+++ b/spec/unit/mutant/subject/method/instance_spec.rb
@@ -48,36 +48,11 @@ RSpec.describe Mutant::Subject::Method::Instance do
 
     subject { object.prepare }
 
-    context 'on non initialize methods' do
-
-      it 'undefines method on scope' do
-        expect { subject }.to change { scope.instance_methods.include?(:foo) }.from(true).to(false)
-      end
-
-      it_should_behave_like 'a command method'
-
+    it 'undefines method on scope' do
+      expect { subject }.to change { scope.instance_methods.include?(:foo) }.from(true).to(false)
     end
 
-    context 'on initialize method' do
-
-      let(:node) do
-        s(:def, :initialize, s(:args))
-      end
-
-      it 'does not write warnings' do
-        warnings = Mutant::WarningFilter.use do
-          subject
-        end
-        expect(warnings).to eql([])
-      end
-
-      it 'undefines method on scope' do
-        subject
-        expect { scope.new }.to raise_error(NoMethodError)
-      end
-
-      it_should_behave_like 'a command method'
-    end
+    it_should_behave_like 'a command method'
   end
 
   describe '#source' do
diff --git a/spec/unit/mutant/warning_expectation_spec.rb b/spec/unit/mutant/warning_expectation_spec.rb
deleted file mode 100644
index 2388f425..00000000
--- a/spec/unit/mutant/warning_expectation_spec.rb
+++ /dev/null
@@ -1,80 +0,0 @@
-RSpec.describe Mutant::WarningExpectation do
-  let(:object) { described_class.new(expected_warnings) }
-
-  let(:expected_warnings) { [] }
-  let(:actual_warnings)   { [] }
-
-  let(:warning_a) { "foo.rb:10: warning: We have a problem!\n" }
-  let(:warning_b) { "bar.rb:10: warning: We have an other problem!\n" }
-
-  describe '#execute' do
-    subject { object.execute(&block) }
-
-    before do
-      @called = false
-    end
-
-    let(:block) do
-      lambda do
-        @called = true
-        actual_warnings.each(&Kernel.method(:warn))
-      end
-    end
-
-    it 'executes block' do
-      expect { subject }.to change { @called }.from(false).to(true)
-    end
-
-    context 'when no warnings occur during block execution' do
-
-      context 'and no warnings are expected' do
-        it_should_behave_like 'a command method'
-      end
-
-      context 'and warnings are expected' do
-        let(:expected_warnings) { [warning_a] }
-
-        before do
-          expect($stderr).to receive(:puts).with("Expected but missing warnings: #{expected_warnings}")
-        end
-
-        it_should_behave_like 'a command method'
-      end
-    end
-
-    context 'when warnings occur during block execution' do
-      let(:actual_warnings) { [warning_a, warning_b] }
-
-      context 'and only some no warnings are expected' do
-        let(:expected_warnings) { [warning_a] }
-
-        it 'raises an expectation error' do
-          expect { subject }.to raise_error(Mutant::WarningExpectation::ExpectationError.new([warning_b], expected_warnings))
-        end
-      end
-
-      context 'and all warnings are expected' do
-        let(:expected_warnings) { [warning_a, warning_b] }
-
-        it_should_behave_like 'a command method'
-      end
-
-      context 'and there is an expected warning missing' do
-        let(:expected_warnings) { [warning_a] }
-        let(:actual_warnings)   { [warning_b] }
-
-        it 'raises an expectation error' do
-          expect { subject }.to raise_error(Mutant::WarningExpectation::ExpectationError.new([warning_b], expected_warnings))
-        end
-      end
-    end
-  end
-end
-
-RSpec.describe Mutant::WarningExpectation::ExpectationError do
-  describe '#message' do
-    subject { described_class.new(['unexpected-a'], ['expected-b']).message }
-
-    it { should eql('Unexpected warnings: ["unexpected-a"], expected: ["expected-b"]') }
-  end
-end