Request: Net ID Conflict Warning

Today another flyer showed up at the field and switched on his telemetry while I was flying. He was using APM Planner 2.0, and he received a warning on the screen that someone else was using the same Net ID.
I would like a similar alert in Mission Planner.
Thank you.

Start by locating Mission Planner's telemetry and Net ID handling, then compare how APM Planner 2.0 detects and displays conflicts. The issue does not name files or tests; done would be a clear on-screen warning when another vehicle is using the same Net ID.

Written by the indexing model from the issue text.