I've long wondered why FOSS developers of successful software don't offer some kind of financial bounty for whistleblowers who reveal that a given legal entity is violating the terms of their license.
Like, I release pretty much everything I create into the extended public domain (CC0/the Unlicense/0BSD), so I very intentionally have no dog in this race, but for those who make different choices for me regarding their public contributions, it just seems logical. Maybe it's just impossible to sue someone for violation of the GPL in a way which makes it easy to come out financially ahead, though.