The Cornell University Library has adopted a policy of not signing e-resources licenses with nondisclosure clauses.
Here's an excerpt from the policy:
To promote openness and fairness among libraries licensing scholarly resources, Cornell University Library will not enter into vendor contracts that require nondisclosure of pricing information or other information that does not constitute a trade secret. All new and renewed licenses submitted with nondisclosure clauses will not be signed but henceforth will be referred to the Associate University Librarian for Scholarly Resources and Special Collections for further negotiation. . . .
It has become apparent to the library community that the anticompetitive conduct engaged in by some publishing firms is in part a result of the inclusion of nondisclosure agreements in contracts.1 As Robert Darnton recently noted, by "keeping the terms secret, … one library cannot negotiate for cheaper rates by citing an advantage obtained by another library."2 For this reason, the International Coalition of Library Consortia's "Statement of Current Perspective and Preferred Practices for the Selection and Purchase of Electronic Information" states that "Non-disclosure language should not be required for any licensing agreement, particularly language that would preclude library consortia from sharing pricing and other significant terms and conditions with other consortia."3 The more that libraries are able to communicate with one another about vendor offers, the better they are able to weigh the costs and benefits of any individual offer. An open market will result in better licensing terms.
Read more about it at "Cornell U. Library Takes a Stand with Journal Vendors: Prices Will Be Made Public."