https://arstechnica.com/tech-policy/2018/05/injury-lawyers-push-ads-to-patients-phones-when-they-go-to-geofenced-ers/

With digital traps in hospitals, there’s no need for personal injury lawyers to chase ambulances these days.

Law firms are using geofencing in hospital emergency rooms to target advertisements to patients’ mobile devices as they seek medical care, according to Philadelphia public radio station WHYY. Geofencing can essentially create a digital perimeter around certain locations and target location-aware devices within the borders of those locations. Patients who unwittingly jump that digital fence may see targeted ads for more than a month, and on multiple devices, the outlet notes.