The fact that "Kizuna" system is full of loopholes is what makes the Power of Friendship the most powerfull force in the universe
Even the vaguest term of Frienship can empowers it so much and if you continue this vague friendship bond thing, it'll become real later on and makes the one who have the Power of Friendship/Bonds become empowered even further, maybe even unlocking a new techniaue, or forms, or demons, or at the very least, a job.
Also I want to believe that the Kizuna Sentai is created by our Bro Gentaro Kisaragi