Unfortunately,
MPSP decided the case isn't collective. The case is archived. However, they haven't denied the right. They archived the case as heterogeneous matter. Heterogeneous implies there isn't enough reputation to be considered homogeneous or collective. A reasonable consumer expects the device to be up and running, not to be modified.
As far as BSD licensed code goes, it mostly boils down to being required to provide notice that BSD code was used and for any BSD licensed code to retain the appropriate license notice. It's really not complicated, you can provide a copy of the code or not, you can't change the license without permission, but you can generally license your patches however you like, so long as it doesn't require changing the license.
The license explicitly states use in source form is permitted. Under copyright law, this is seen as a permission, not a release promise, where the license is seen as a unilateral matter. However, under contract and consumer law, this can be framed as an actual requirement of sources release, where the license is seen as a bilateral matter.
For the license to be framed as a contract, there must exist an intended beneficiary. The intended beneficiary for the "use in source form" clause is the developer. For the license to be framed in a consumption relationship, there must exist commerce. The FTC Act prohibits deceptive or unfair acts or practices in or affecting commerce. However, FTC may only act if a case is collective. The deception is triggered in the representation of a right that is practically unavailable. The FTC could argue this is a misrepresentation of material facts to a subset of consumers (developers). The unfairness is triggered in depriving users of the ability to exercise a right explicitly granted in the license, creating unavoidable harm.
For FTC to act, the strategy isn't just to report the source code is missing, but to demonstrate that the refusal to provide it causes unavoidable harm to a significant number of people who relied on the promises ("use in source form") of the BSD license.
Contrary to what
bvdw78 stated, it isn't required to falsely market the product as open-source. The impression the BSD license leaves is enough to frame a case as deceptive or unfair.