For follow-me features, use drones like the HoverAir X1 or DJI Mini series which have advanced obstacle avoidance.
Retrieve drones immediately after use to prevent them from being moved to a distant nest. SDTeen Drone Stalker
In the U.S., you can report unsafe or illegal drone activity to the FAA . For follow-me features, use drones like the HoverAir
For legitimate pilots looking to avoid being perceived as a "stalker": For follow-me features