Twitter insists that tracking be switched on to access it - whether you are a member or not.
If you have low security settings set on your device, tracking will be on and Twitter (and anyone who can access their data) can track where you are. In some systems even medium security will leave tracking on. It is only the highest security settings that should guarantee that tracking is blocked.
If you have ever wondered why you suddenly see an article pop up for "People in Tulle* are looking at this" (* if Tulle is a large city near you - choose any large town or city near you to replace Tulle), then that is because someone is tracking your location or approximate location.