The Apostle Paul writes to some of his life’s best friends — the loving, supporting believers of Philippi. And he says to them in chapter 1:
7 “It is right for me to feel this way about you all, because I hold you in my heart, for you are all partakers with me of grace, both in my imprisonment and in the defense and confirmation of the gospel.
8 For God is my witness, how I yearn for you all with the affection of Christ Jesus.
9 And it is my prayer that your love may abound more and more, with knowledge and all discernment,”
There are a lot of deep “connection phrases” there in those verses (ie. hold you in my heart, you are partakers with me, I yearn for you with all affection etc. ) What I see Paul describing is a rich, mutual sharing where each party has each other’s best interests in mind. They really like and love each other. The Philippians want Paul to flourish, and Paul wants the same for them.
They are deep, spiritual friends. Only friends who know that other friends have their best interests at heart will open themselves accountably.
Therefore, accountability is spiritual friendship operating at its very best.
Holy Minestrone 
I like your definition of accountability. Accountability will flow out of a healthy spiritual friendship. Good stuff Pastor Rob!