I'm not a fan of
secret security, security the thief doesn't know is there until he damages or steals your bike. And what will you really do once your bike is stolen? Track it and steal it back? Go to jail for B&E. Hurt the thief? Go to jail for assault. Tell the police? They knock on the door and thief says "what bike?". By the time a warrant is issued it will be... what bike?
Far better to attempt to keep a thief from starting to steal. Like most here I'm sure, I've owned a hundred pounds of locks and the Abus Bordo Granit X-Plus
6500 Foldable Lock is the
Bes Dam Lock I've owned! Although that would change IF my bike gets stolen