license clarification

validation.py

@@ -60,12 +60,12 @@ def validate_croissant(json_data):
         missing = [f for f in REQUIRED_SCHEMA_FIELDS if not json_data.get(f)]
         if missing:
             return True, (
-                "The dataset passes Croissant schema validation, but the `license` field is missing. "
-                "Please add a `license` field to your Croissant file. "
-                "Croissant recommends using the URL of a known license, e.g. one of the licenses listed at "
-                "<a href='https://spdx.org/licenses/' target='_blank'>https://spdx.org/licenses/</a>. "
-                "Note that if your paper is accepted at NeurIPS, a permissive license will be required."
-            ), "warning"
+                "The `license` field is missing. This is required for NeurIPS dataset submissions. "
+                "Please add a `license` field to your Croissant file with the name or URL of the licence governing your dataset. "
+                "Where possible, use <a href='https://www.kaggle.com/discussions/getting-started/116476' target='_blank'>open licenses</a> that "
+                "allow reuse and reproducibility. However, when the dataset contains sensitive data or stricter licensing is unavoidable, "
+                "please select an appropriate license that is as open as possible given the constraints."
+            ), "error"
         return True, "The dataset passes Croissant validation.", "pass"
     except mlc.ValidationError as e:
         error_details = traceback.format_exc()