You are publicly calling into question Mibbit's integrity here, and suggesting that there's an incentive to give Freenode false information about users' IP addresses. Why?
Regardless of Mibbit's integrity -- of which I have no opinion, and am not calling into question -- freenode has absolutely no responsibility (contractual, moral, or otherwise) to extend their trust to any third party.
If Mibbit wishes to resolve the issue they can enter into a contract with Freenode to establish trust. Mibbit can provide a financial incentive and contractual guarantees, and in return Freenode can agree to extend Mibbit trust and administrative resources.
Regardless of Mibbit's integrity -- of which I have no opinion, and am not calling into question -- freenode has absolutely no responsibility (contractual, moral, or otherwise) to extend their trust to any third party.
If Mibbit wishes to resolve the issue they can enter into a contract with Freenode to establish trust. Mibbit can provide a financial incentive and contractual guarantees, and in return Freenode can agree to extend Mibbit trust and administrative resources.