Fix unsafe use of BaseNode

apps/openmw/mwmechanics/mechanicsmanagerimp.cpp

@@ -1214,7 +1214,7 @@ namespace MWMechanics
 
     bool MechanicsManager::awarenessCheck(const MWWorld::Ptr &ptr, const MWWorld::Ptr &observer)
     {
-        if (observer.getClass().getCreatureStats(observer).isDead())
+        if (observer.getClass().getCreatureStats(observer).isDead() || !observer.getRefData().isEnabled())
             return false;
 
         const MWWorld::Store<ESM::GameSetting>& store = MWBase::Environment::get().getWorld()->getStore().get<ESM::GameSetting>();