@Cryptopathic no need to enforce it even - people will naturally start ignoring those that have no provenance proof in favour of those that do, which will naturally incentivise people to participate
@grhmc Imo the main reason nixpkgs is so sticky is that it is the only way you can get pkgs into the only default binary cache.
Showing new users how to enable custom caches just for nix flakes is a PITA.
If flakehub was a default substituter in mainline Nix, it’d help adoption a lot.