Add to Protocols FAQ

src/protocols/faq.md

@@ -181,6 +181,39 @@ Blocking events within a [Source Schema](/docs/connections/sources/schema/) or [
 
 Warehouse connectors don't use data type definitions for schema creation. The [data types](/docs/connections/storage/warehouses/schema/#data-types) for columns are inferred from the first event that comes in from the source.
 
+### Why are unplanned properties not showing up as blocked in my Source Schema, even though I've set the Schema Configuration to omit them?
+
+Next to the Event Name column in your [Source Schema](/docs/connections/sources/schema/) are two columns:  Allowed and Blocked. If you configure your [Schema Configuration](https://segment.com/docs/protocols/enforce/schema-configuration/) to Block Unplanned Events and Omit Properties, the Source Schema only shows a property or trait as blocked when the _entire event is blocked_ because it’s unplanned and not part of the Tracking Plan. The Block Unplanned Events and Omit Properties settings are only be enforced if the property is an unplanned name, not an unplanned value.
+
+To show a blocked value for a property/trait in your Source Schema, you'll need to trigger a violation, which can only be done using the JSON Schema. Once you configure your Schema Configuration to Omit Properties, the property or trait is shown as blocked.
+
+See an example payload below: 
+
+```json
+"protocols": {
+      "omitted": [
+        "newProperty"
+      ],
+      "omitted_on_violation": [
+        "integer",
+        "string"
+      ],
+      "sourceId": "1234",
+      "violations": [
+        {
+          "type": "Invalid Type",
+          "field": "properties.integer",
+          "description": "Invalid type. Expected: integer, given: number"
+        },
+        {
+          "type": "Invalid Type",
+          "field": "properties.string",
+          "description": "Invalid type. Expected: string, given: integer"
+        }
+      ]
+```
+![A screenshot of the Source Schema page, with an event expanded to display a blocked property, newProperty.](images/protocols-faq-blocked-events.png)
+
 ### Can I use schema controls to block events forwarded to my source from another source?
 
 You can only use schema controls to block events at the point that they are ingested into Segment. When you forward an event that Segment has previously ingested from another source, that event bypasses the pipeline that Segment uses to block events and cannot be blocked a second time.