"II. The 2008 Amendments to the FISA
While the underlying actions were pending in district court, and partially in response to these suits, Congress enacted the FISA Amendments Act of 2008, Pub. L. No. 110-261, 122 Stat. 2435, codified at 50 U.S.C. § 1885a. Among the amendments is § 802, an immunity provision and related procedures that are triggered if the United States Attorney General certifies to one or more of five conditions. In such case, no civil action may be maintained “against any person for providing assistance to an element of the intelligence community.” § 802(a)."
This to me says such an action would not even get off the ground let alone them having to answer the "what did you think the $10m was buying" question.
1. any assistance by that person was provided pursuant to an order of the court established under section 103(a) directing such assistance;
2. any assistance by that person was provided pursuant to a certification in writing under section 2511(2)(a)(ii)(B) or 2709(b) of title 18, United States Code;
3. any assistance by that person was provided pursuant to a directive under section 102(a)(4), 105B(e), as added by section 2 of the Protect America Act of 2007 (Public Law 110–55), or 702(h) directing such assistance;
4. in the case of a covered civil action, the assistance alleged to have been provided by the electronic communication service provider was—
A) in connection with an intelligence activity involving communications that was—
i) authorized by the President during the period beginning on September 11, 2001, and ending on January 17, 2007; and
ii) designed to detect or prevent a terrorist attack, or activities in preparation for a terrorist attack, against the United States; and
B) the subject of a written request or directive, or a series of written requests or directives, from the Attorney General or the head of an element of the intelligence community (or the deputy of such person) to the electronic communication service provider indicating that the activity was—
i) authorized by the President; and
ii) determined to be lawful; or
5. the person did not provide the alleged assistance.
To argue they were actively working with the NSA on an intelligence operation, while possibly granting them immunity there, would likely cost them even more customers.