Also don't forget that relative effort matters too. Consider "The Club" protection for cars - in a lot, the one with The Club is chosen last to break into just

Also don't forget that relative effort matters too. Consider "The Club" protection for cars - in a lot, the one with The Club is chosen last to break into just due to its relative difficulty. (Weighted against the potential upside, obviously.) The port knocking itself may actually be the strongest link in the chain, despite it being one of obscurity, if the population of targets in your "value pool" is large enough so that you are always below a sufficient number of others without knocking enabled, since all attackers will bounce to those when they realize they are not knocked.