What this really looks like is a procrastination tool so that somebody can sit back and relax when they see someone else is changing the same area in the source.
I'd love to hear why I'm wrong.
We tried quite a few processes to reduce it and they'd all work for a few weeks but inevitably we'd revert back to old behaviour pretty fast.
On your point about it being a procrastination tool, I'd love it if my team members took a minute to stop work and converse with the others if they're working on the same bit of code! Aside from time saved fixing a potential conflict it's probably indicative that a particular bit of the system needs to be refactored. Anything that can help guide the decision to refactor is probably a force for good but we'll see. H
It makes sense that the tool would highlight parts of the codebase that need refactoring. I am a bit confused about what would be communicated between two engineers on a piece of code though. Would it be "hey, could you do XYZ as part of your change"? Or "hey, please don't change this piece of code until I've changed it"?