QHM Nav Warn: a double warning

A bland but helpful statement from QHM Portsmouth today:
Nav Warn 08/09 Nab Outer No:1 Buoy
The Nab Outer no:1 Buoy Pos. 50 38.18N 000 56.88W has a damaged top mark. Mariners navigating in this vicinity should do so with caution.

Now have a think about this one. This is a large, well-lit and charted buoy on the main approach channel to Portsmouth. Buoys don't just fall apart on a clear day, something large and blundering must have hit it. Could this be any more of a warning to get the heck out of the way of large ships in the area? They can't always miss a large buoy, let alone a small angling boat.