There is no evidence that supports that in ANY way. 10 people can be standing next to each other, all with cell phones in their pockets, all running 2.4 gig transmitters with returning telemetry and no one has issues. Why would we mysteriously have an issue with a drone in a far less flooded situation?
The "grid" only showing is because the map defaults to roads only. There is a setting to change the layers on the full screen map to use satellite or hybrid maps as well.
You do want to have an active proper map to work off of in case of a fly-away at very least. You can navigate yourself to the last know point of the drone.