I was under the impression that this mod was introduced after the loss of a S61 last year in the UK. If I remember right, the No 5 engine bearing failed, causing a fire which quickly spread to the other engine and the back of the gearbox. Fortunately they managed to get the a/c on the ground within 90 secs of the first engine fire warning, just before they lost all hydraulics. A couple of minutes later the gearbox fell through the roof of the cabin. All the guys got out without injury.
I know exactly what my reaction would be to an engine chip warning - exactly what it says on the EOP!