I meant to post a warning about this a couple of weeks ago. I've encountered several cars over the last couple of months where the rear shock absorber spring support has corroded to the point where it has become seriously weakened. One of these cars had passed it's MOT two days previously; the problem is that it's not always immediately obvious, as the top of the plate is covered by a rubber pad, and surface rust on the underside is not uncommon.
I would recommend anyone who owns a car that is over six years old or has covered in excess of 100,000 miles to thoroughly inspect these plates for rust, and if you have any doubts, take the car to your garage for a more in-depth assessment (ideally the wheels need to be removed).
Both the above posters were very lucky that the consequences were not more serious.