So, do they run into problems with anything that uses JSON?
(JSON has a clause in their license: "The Software shall be used for Good, not Evil.")
(JSON has a clause in their license: "The Software shall be used for Good, not Evil.")
The specification diagrams or text on json.org? Similarly non free.
The JSON format itself? Arguably not copyrightable. Maybe patentable, had Crockford tried 20 years ago, but that's more an argument for the lunacy of many software patents.
If you're concerned about the implications of the JSON license on JSON implementations, wait until you hear about the ISO8601 spec's license