Jeremy's checkbox widget will also revert to true/false if you only pass it a single option. (Not sure if this was already the case when you created this notebook.)

I think it might have been! It’s not exactly true/false, since the truthy value is the `value` you provide. It also has a more verbose API for the simple cases this checkbox is designed for.

Nice. Another approach: NOT NOT, Who's There!!: https://observablehq.com/@mariodelgadosr/not-not-whos-there