One of the features I teach in my advanced Twitter classes is use of Twitter to find marketing leads in your area using the Advanced Search function. Researchers have been using Twitter’s geolocation and language identification data, but there are some limitations, as this paper points out.
Assuming you are examining status updates by hand, you are unlikely to detect false positives. Because most people don’t embed location services, your bigger problem will be false negatives, i.e. status updates which the search should have revealed but doesn’t.