This seems a pretty successful business model, actually.
Find companies who commit technical violations of California's background check law (which the Court of Appeal correctly notes may perhaps "be 'technical violations,' [but] they are violations nonetheless"), find 141 clients and file individual lawsuits on behalf of each, and obtain the $10,000 minimum statutory damages for each of them. As well as, pursuant to that same statute, attorney's fees and costs.
That's a fair chunk of change.
The Court of Appeal says that the strategy works. At least here, and at least with respect to standing. In California, at least (unlike federal courts), there's no "case and controversy" requirement, so pure statutory standing works.
Nice work if you can get it.