Location tags enable tracking of personal belongings. This is achieved locally, e.g., via Bluetooth with a paired phone, and remotely, by piggybacking on the location reported by location-reporting devices which come into proximity of a tag. There has been anecdotal evidence that location tags are also misused to stalk people. This paper studies the performance of the two most popular location tags (Apple's AirTag and Samsung's SmartTag) through controlled experiments -- with a known large distribution of location-reporting devices -- as well as in-the-wild experiments -- with no control on the number and kind of reporting devices encountered, thus emulating real-life use-cases. We find that both tags achieve similar performance, e.g., they are located 60% of the times in about 10 minutes within a 100 meter radius. It follows that real time stalking via location tags is impractical, even when both tags are concurrently deployed which achieves comparable accuracy in half the time. Nevertheless, half of a victim's movements can be backtracked accurately (10 meter error) with just a one-hour delay.

翻译：位置标签能够追踪个人物品。这既可以通过本地方式实现（例如，通过蓝牙与配对手机连接），也可以通过远程方式实现，即借助靠近标签的位置报告设备所报告的位置。有传闻证据表明，位置标签也被滥用于跟踪他人。本文通过控制实验（即已知位置报告设备的大规模分布）以及在野外实验（即对遇到的报告设备的数量和种类不加控制，从而模拟真实生活场景）研究了两种最流行的位置标签（苹果的AirTag和三星的SmartTag）的性能。我们发现两种标签性能相似，例如，在约10分钟内，60%的情况下可在100米半径范围内定位它们。因此，通过位置标签进行实时跟踪是不切实际的，即使同时部署两种标签也只能将定位准确性相似的时间缩短一半。尽管如此，受害者一半的行踪可以以10米的误差在仅延迟一小时的情况下被精确回溯。