I can pin/unpin other cities, but not Austin. It is currently pinned, but attempts to unpin it result in a HTTP 422 error from the request POST /running_cities/475767/unpin (I dropped the protocol and domain on that URL so the forum doesn’t try and create a preview.) The response is empty, let me know if you want any of the specific headers that are returned (there are many).
On cities where un-pinning works, that request results in a HTTP 200 as you’d expect.
Fair … I’ll look into disabling the button for the default city.
Update: OK, next release will disable the button & indicate the default city with a small home icon … this change doesn’t provide further clarity as to why the city can’t be unpinned, but it does remove the confusion around whether anything was broken