Customers.md

@@ -60,6 +60,8 @@ There are three client agendas: "admin" (ID: 10), "employee" (ID: 11) and "custo
 
 These IDs should not change, but they could in theory.
 
+Only a user with agenda "admin" may change (create/delete) agenda assignments.
+
 To list them:
 
 ```