> One outcome of this fight might be that government organizations are directed to use more proprietary communication methods which would be a poor outcome for everyone involved.
I agree with the rest of your argument, but I think that this part is not necessarily a good example of the risks. Far easier would be to use a shared key between the app and the site, and thus use encryption to prevent reading the data, while still sending it in JSON over HTTPS. A pinned certificate would do the trick, at least on phones which prevent the user from inspecting app bundles.
I think it depends on the outcome of the case - I could see some possible resolution like the Swedish supreme court declaring that JSON counts as a public record and that forcing a block on prohibitive encryption of JSON endpoints offered by the government (assuming everything the OP said about constitutionality is correct).
We've seen such bizarre technical decisions from high courts before.
I don't know - I think all legal systems use precedents to a certain extent - they're just extremely formalized in America and Britain. Sorry but I'm not familiar enough with their system to reply with confidence but I would say that if a high court in a country rules a certain way, even if that isn't binding to future rulings, it will cause people to adjust their behavior to avoid falling into a trap that's been clearly called out already.
I agree with the rest of your argument, but I think that this part is not necessarily a good example of the risks. Far easier would be to use a shared key between the app and the site, and thus use encryption to prevent reading the data, while still sending it in JSON over HTTPS. A pinned certificate would do the trick, at least on phones which prevent the user from inspecting app bundles.