This may be true in some sense but the warrant was to Google, not the carrier. If you just tell your location services not to share your location with Google (much less turn on airplane mode or turn off the device), you won’t be in their database. There is definitely a wrong way to do this, which made news a few months ago. But if you disable it correctly, your location won’t be sent. I haven’t verified this personally, but it’s easy enough to detect. I don’t buy in to easily-disprovable conspiracy theories even if I haven’t disproved them personally.
Of course, they could also serve a reverse warrant to all the major carriers and demand location data, and who knows, maybe your “turned off” phone leaks that, but that’s not what the OP is about.
