They're a US mobile telco, a warrant canary wouldn't last a year here. That's not, on the surface, a useful differentiator between mobile service providers. Did you have a specific kind of warrant canary in mind that would act as a differentiator, or is there some aspect of warrant canaries I've overlooked that makes them meaningful for US telecoms that are governed by US federal and state laws, or..?

This is correct. We talked about canaries a bunch internally and came to the same conclusion-- not really worth it in this context (but please do offer up a model that makes sense if you see one).

I came to the conclusion the best we can do is what you see in our privacy policy: we notify our users when we're served with legal process that is not subject to a gag order, and we pledge to push back on any law enforcement request we receive that is not properly formed or narrowly tailored as required by law. I'd love input/ideas on how to be stronger here.