There is no such thing as "fines by FISA court". FISA doesn't hear adversarial cases and doesn't have statutory authority or even subject matter jurisdiction to enforce compliance on private actors. FISA is an authorizer for other government bodies, who then use ordinary Article III courts to enforce compliance. Other than the fact that they're staffed by Article III judges and not directly overseen by Article III courts, the FISA court functions like a magistrate court, not a normal court. So: I immediately distrust the source.
People are going to come back and say "well yeah that's just what they tell you about FISA court, but I bet FISA courts fine people all the time", but no, it's deeper than that: private actors aren't parties to FISA cases. It's best to think of them as exclusively resolving conflicts between government bodies.
You are just wrong:
> In some circumstances, nongovernmental parties may litigate the lawfulness of FISA orders or directives to provide information or assistance to the government. For example:
> A private company or individual that has been served with a directive to assist in acquiring information under Section 702 may petition the FISC to modify or set aside the directive. Conversely, the government may petition the FISC to compel the recipient to comply with the directive.
> In responding to the government’s petition, the private party has the opportunity to show cause for the noncompliance or argue that the order should not be enforced as issued.
> In 2007, Yahoo! Inc. refused to comply with directives issued by the government under provisions of FISA that have been replaced by Section 702. The government filed a motion with the FISC to compel compliance.
https://www.fisc.uscourts.gov/about-foreign-intelligence-sur...
The warrants the court issues do apply to private parties. Failure to comply with a warrant is contempt of court and the court can compel compliance by fines and other sanctions. You can read what that looks like in this FISA court ruling against Yahoo.
PDF warning: https://donohueintellaw.ll.georgetown.edu/sites/default/file...
It was a big company that said they'd be fined per day for non-compliance with mass surveillance. Core Secrets etc says that was done by FBI for FISA warrants. So, whoever enforces that.
I dont know the mechanics of it, like jurisdiction. It might be as you say. I just know they and their targets were both clear at different times they could force a company to do it.