diff --git a/CHANGELOG b/CHANGELOG
index fa8673018..5da150183 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,6 +1,9 @@
 Changes between 2.0.0 and 2.0.1.dev1
 ----------------------------------------------
 
+- improve behaviour/warnings when running on top of "python -OO"
+  (assertions and docstrings are turned off, leading to potential
+  false positives)
 - introduce a pytest_cmdline_processargs(args) hook
   to allow dynamic computation of command line arguments.
   This fixes a regression because py.test prior to 2.0
diff --git a/_pytest/assertion.py b/_pytest/assertion.py
index 71d26ab1c..9c7143bb8 100644
--- a/_pytest/assertion.py
+++ b/_pytest/assertion.py
@@ -17,8 +17,8 @@ def pytest_configure(config):
     # turn call the hooks defined here as part of the
     # DebugInterpreter.
     config._monkeypatch = m = monkeypatch()
+    warn_about_missing_assertion()
     if not config.getvalue("noassert") and not config.getvalue("nomagic"):
-        warn_about_missing_assertion()
         def callbinrepr(op, left, right):
             hook_result = config.hook.pytest_assertrepr_compare(
                 config=config, op=op, left=left, right=right)
@@ -38,9 +38,8 @@ def warn_about_missing_assertion():
     except AssertionError:
         pass
     else:
-        py.std.warnings.warn("Assertions are turned off!"
-                             " (are you using python -O?)")
-
+        sys.stderr.write("WARNING: failing tests may report as passing because "
+        "assertions are turned off!  (are you using python -O?)\n")
 
 # Provide basestring in python3
 try:
diff --git a/_pytest/core.py b/_pytest/core.py
index 5c202e28d..aae7c1c6e 100644
--- a/_pytest/core.py
+++ b/_pytest/core.py
@@ -362,9 +362,6 @@ class HookRelay:
         added = False
         for name, method in vars(hookspecs).items():
             if name.startswith(prefix):
-                if not method.__doc__:
-                    raise ValueError("docstring required for hook %r, in %r"
-                        % (method, hookspecs))
                 firstresult = getattr(method, 'firstresult', False)
                 hc = HookCaller(self, name, firstresult=firstresult)
                 setattr(self, name, hc)
diff --git a/testing/acceptance_test.py b/testing/acceptance_test.py
index d05d9e189..a53afe7fc 100644
--- a/testing/acceptance_test.py
+++ b/testing/acceptance_test.py
@@ -218,6 +218,12 @@ class TestGeneralUsage:
         assert res.ret
         res.stderr.fnmatch_lines(["*ERROR*not found*"])
 
+    def test_docstring_on_hookspec(self):
+        from _pytest import hookspec
+        for name, value in vars(hookspec).items():
+            if name.startswith("pytest_"):
+                assert value.__doc__, "no docstring for %s" % name
+
 class TestInvocationVariants:
     def test_earlyinit(self, testdir):
         p = testdir.makepyfile("""
diff --git a/testing/test_assertion.py b/testing/test_assertion.py
index e153f6546..b4c74b0de 100644
--- a/testing/test_assertion.py
+++ b/testing/test_assertion.py
@@ -201,3 +201,14 @@ def test_traceback_failure(testdir):
         "*test_traceback_failure.py:4: AssertionError"
     ])
 
+@pytest.mark.skipif("sys.version_info < (2,5)")
+def test_warn_missing(testdir):
+    p1 = testdir.makepyfile("")
+    result = testdir.run(sys.executable, "-OO", "-m", "pytest", "-h")
+    result.stderr.fnmatch_lines([
+        "*WARNING*assertion*",
+    ])
+    result = testdir.run(sys.executable, "-OO", "-m", "pytest", "--no-assert")
+    result.stderr.fnmatch_lines([
+        "*WARNING*assertion*",
+    ])
diff --git a/testing/test_core.py b/testing/test_core.py
index 3bcf681af..76721974e 100644
--- a/testing/test_core.py
+++ b/testing/test_core.py
@@ -319,25 +319,6 @@ class TestPytestPluginInteractions:
         res = config.hook.pytest_myhook(xyz=10)
         assert res == [11]
 
-    def test_addhooks_docstring_error(self, testdir):
-        newhooks = testdir.makepyfile(newhooks="""
-            class A: # no pytest_ prefix
-                pass
-            def pytest_myhook(xyz):
-                pass
-        """)
-        conf = testdir.makeconftest("""
-            import sys ; sys.path.insert(0, '.')
-            import newhooks
-            def pytest_addhooks(pluginmanager):
-                pluginmanager.addhooks(newhooks)
-        """)
-        res = testdir.runpytest()
-        assert res.ret != 0
-        res.stderr.fnmatch_lines([
-            "*docstring*pytest_myhook*newhooks*"
-        ])
-
     def test_addhooks_nohooks(self, testdir):
         conf = testdir.makeconftest("""
             import sys