Lightnings: If a factory is hit by a lightning, directly or indirectly, a heavy current will flow along ground routing. If it's not well earthed, like in an old plant, impedance of ground routing is high and relevant voltage drop occur. So, between two ground points CMN is introduced. Here also, ground mesh technique helps in drastically reducing CMN.
First, this is not a means where I would care about glitch free operation, more about the equipment surviving.
Second, I have yet to see an insustrial plant with a ground mesh.

Erik