I think this does the unregistered correctly... checking..

custom_components/ecowitt/__init__.py

@@ -47,6 +47,9 @@
     DEVICE_CLASS_TEMPERATURE,
     DEVICE_CLASS_PRESSURE,
     DEVICE_CLASS_TIMESTAMP,
+)
+
+from homeassistant.components.binary_sensor import (
     DEVICE_CLASS_MOISTURE,
 )
 
@@ -597,37 +600,45 @@ async def close_server(*args):
     # # go to sleep until we get the first report
     # await ws.wait_for_valid_data()
 
-    def check_and_append_sensor(sensor):
-        """Check the sensor for validity, and append to appropriate list."""
-        if sensor not in SENSOR_TYPES:
-            if sensor not in IGNORED_SENSORS:
-                _LOGGER.warning("Unhandled sensor type %s", sensor)
-            return
-
+    def check_imp_metric_sensor(sensor):
+        """Check if this is the wrong sensor for our config (imp/metric)."""
         # Is this a metric or imperial sensor, lookup and skip
         name, uom, kind, device_class, icon, metric = SENSOR_TYPES[sensor]
         if "baro" in sensor:
             if (conf[CONF_UNIT_BARO] == CONF_UNIT_SYSTEM_IMPERIAL
                     and metric == S_METRIC):
-                return
+                return False
             if (conf[CONF_UNIT_BARO] == CONF_UNIT_SYSTEM_METRIC
                     and metric == S_IMPERIAL):
-                return
+                return False
         if "rain" in sensor:
             if (conf[CONF_UNIT_RAIN] == CONF_UNIT_SYSTEM_IMPERIAL
                     and metric == S_METRIC):
-                return
+                return False
             if (conf[CONF_UNIT_RAIN] == CONF_UNIT_SYSTEM_METRIC
                     and metric == S_IMPERIAL):
-                return
+                return False
         if "wind" in sensor:
             if (conf[CONF_UNIT_WIND] == CONF_UNIT_SYSTEM_IMPERIAL
                     and metric == S_METRIC):
-                return
+                return False
             if (conf[CONF_UNIT_WIND] == CONF_UNIT_SYSTEM_METRIC
                     and metric == S_IMPERIAL):
-                return
+                return False
+        return True
 
+    def check_and_append_sensor(sensor):
+        """Check the sensor for validity, and append to appropriate list."""
+        if sensor not in SENSOR_TYPES:
+            if sensor not in IGNORED_SENSORS:
+                _LOGGER.warning("Unhandled sensor type %s", sensor)
+            return
+
+        # Is this a metric or imperial sensor, lookup and skip
+        if not check_imp_metric_sensor(sensor):
+            return
+
+        name, uom, kind, device_class, icon, metric = SENSOR_TYPES[sensor]
         if kind == TYPE_SENSOR:
             sensor_sensors.append(sensor)
         if kind == TYPE_BINARY_SENSOR:
@@ -683,7 +694,10 @@ async def _async_ecowitt_update_cb(weather_data):
                 if sensor not in IGNORED_SENSORS:
                     _LOGGER.warning("Unhandled sensor type %s value %s, "
                                     + "file a PR.", sensor, weather_data[sensor])
-            if sensor not in sensor_sensors and sensor not in binary_sensors:
+            elif (sensor not in sensor_sensors
+                  and sensor not in binary_sensors
+                  and sensor not in IGNORED_SENSORS
+                  and check_imp_metric_sensor(sensor)):
                 _LOGGER.warning("Unregistered sensor type %s value %s received.",
                                 sensor, weather_data[sensor])
         async_dispatcher_send(hass, DOMAIN)