Add the respectable velvet hammer motto

README.md

@@ -39,6 +39,11 @@ the engine's governing temperament:
 
 > The hammer permits no silent widening of scope.
 
+And its project motto keeps the same principle courteous:
+
+> If one must be struck by security policy, let it be by a respectable velvet
+> hammer: precise, accountable, and courteous enough to explain why.
+
 ## Project documents
 
 - [Coarse-grained concept](CONCEPT.md)