diff --git a/src/czml3/__init__.py b/src/czml3/__init__.py
index 1b50d81..6ea2121 100644
--- a/src/czml3/__init__.py
+++ b/src/czml3/__init__.py
@@ -1,5 +1,5 @@
 from .core import CZML_VERSION, Document, Packet
 
-__version__ = "2.2.3"
+__version__ = "2.3.0"
 
 __all__ = ["Document", "Packet", "CZML_VERSION"]
diff --git a/src/czml3/base.py b/src/czml3/base.py
index b18216b..ed8fcce 100644
--- a/src/czml3/base.py
+++ b/src/czml3/base.py
@@ -1,26 +1,25 @@
-from typing import Any
+import sys
 
-from pydantic import BaseModel, model_validator
+from pydantic import BaseModel, ConfigDict, model_validator
+
+if sys.version_info[1] >= 11:
+    from typing import Self
+else:
+    from typing_extensions import Self  # pragma: no cover
 
 NON_DELETE_PROPERTIES = ["id", "delete"]
 
 
 class BaseCZMLObject(BaseModel):
-    @model_validator(mode="before")
-    @classmethod
-    def validate_model_before(cls, data: dict[str, Any]) -> Any:
-        if (
-            data is not None
-            and isinstance(data, dict)
-            and "delete" in data
-            and data["delete"]
-        ):
-            return {
-                "delete": True,
-                "id": data.get("id"),
-                **{k: None for k in data if k not in NON_DELETE_PROPERTIES},
-            }
-        return data
+    model_config = ConfigDict(extra="forbid")
+
+    @model_validator(mode="after")
+    def check_delete(self) -> Self:
+        if hasattr(self, "delete") and self.delete:
+            for k in self.model_fields:
+                if k not in NON_DELETE_PROPERTIES and getattr(self, k) is not None:
+                    setattr(self, k, None)
+        return self
 
     def __str__(self) -> str:
         return self.to_json()
diff --git a/src/czml3/types.py b/src/czml3/types.py
index f3a016f..e82443c 100644
--- a/src/czml3/types.py
+++ b/src/czml3/types.py
@@ -18,7 +18,7 @@
 if sys.version_info[1] >= 11:
     from typing import Self
 else:
-    from typing_extensions import Self
+    from typing_extensions import Self  # pragma: no cover
 
 TYPE_MAPPING = {bool: "boolean"}
 
diff --git a/tests/test_properties.py b/tests/test_properties.py
index bcc1152..8e2f222 100644
--- a/tests/test_properties.py
+++ b/tests/test_properties.py
@@ -618,21 +618,32 @@ def test_material_checkerboard():
 
 
 def test_position_has_delete():
-    pos = Position(delete=True, cartesian=[])
-
+    expected_result = """{
+    "delete": true
+}"""
+    pos = Position(delete=True, cartesian=[0, 0, 0])
     assert pos.delete
+    assert str(pos) == expected_result
 
 
 def test_position_list_has_delete():
-    pos = PositionList(delete=True, cartesian=[])
-
+    expected_result = """{
+    "delete": true
+}"""
+    pos = PositionList(delete=True, cartesian=[0, 0, 0])
     assert pos.delete
+    assert str(pos) == expected_result
 
 
 def test_position_list_of_lists_has_delete():
-    pos = PositionListOfLists(delete=True, cartesian=[])
-
+    expected_result = """{
+    "delete": true
+}"""
+    pos = PositionListOfLists(
+        delete=True, cartesian=[[20.0, 20.0, 0.0], [10.0, 10.0, 0.0]]
+    )
     assert pos.delete
+    assert str(pos) == expected_result
 
 
 def test_position_no_values_raises_error():
@@ -787,9 +798,12 @@ def test_viewfrom_cartesian():
 
 
 def test_viewfrom_has_delete():
-    v = ViewFrom(delete=True, cartesian=[14.0, 12.0])
-
+    expected_result = """{
+    "delete": true
+}"""
+    v = ViewFrom(delete=True, cartesian=[14.0, 12.0, 1.0])
     assert v.delete
+    assert str(v) == expected_result
 
 
 def test_viewfrom_no_values_raises_error():
@@ -1789,6 +1803,26 @@ def test_packet_billboard():
     assert str(packet) == expected_result
 
 
+def test_delete():
+    expected_result = """{
+    "delete": true
+}"""
+    p = PositionList(
+        cartographicDegrees=CartographicDegreesListValue(values=[20, 30, 10]),
+        delete=True,
+    )
+    assert str(p) == expected_result
+
+
+def test_forbid_extras():
+    with pytest.raises(ValidationError):
+        PositionList(
+            cartographicDegrees=CartographicDegreesListValue(values=[20, 30, 10]),
+            delete=True,
+            a=1,  # type: ignore[call-arg]
+        )
+
+
 # @pytest.mark.xfail(reason="Reference value needs further clarifying")
 # def test_uri_ref():
 #     expected_result = """{