Answer
DB2 ignores layer locks on nonversioned data and allows updates to occur. This has been documented in two cases:
Case 1:
1. The owner of a layer grants select privileges to user2.
2. User2 locks the layer with a read lock or a write lock.
3. The owner successfully inserts data into the layer.
Case 2:
1. The owner grants select/insert/update/delete privileges to user2.
2. Either user2 or the owner locks the layer.
3. The user who does not own the lock on the layer can successfully insert data.