There is a "I'll scratch your back if you scratch mine" between drivers and controllers.

A driver needs to clock off on time, but they are running late. A controller will regulate the service.

In return, the driver may just "keep going" if asked by the controllers when there is a fault.

Flip that around, driver sees a red warning light, tells control of this. Controller tells driver to continue, driver doesn't. Controller then won't do any more favours.

I imagine this is what the "briefing" is all about - setting in stone what should be happening.

The obvious answer is for the company to get it's act together so that staff don't feel like they have to mask what is happening on the road. But that would require a properly resourced control team and more engineering staff. But as we all know GNE made a bunch of staff redundant not long ago and Big Nige thinks they are fully resourced engineering wise lol