In fairness all the bikes that have had failures that i know of have been low mileage with no obvious reasons for the links to fail mechanically.
The metalurgist that was hired to look at Scott's said the tests showed the link broke in one catastrophic failure with no signs of pre failure cracking or impacts. His linkage bearings etc were all fine.
The suggestion is the link is breaking from a twisting action rather than compresssion or extension. All have snapped at the same places across the top and down the back as if the thin leg is bent around the point it meets the swingarm. a bit like bending a ruler over the edge of a table.
Unlike some metals Aluminium is a memory metal. Every flex reduces it's strength and stiffens the metal making it brittle. You've all bent a coke can ring pull back. Bend it 5 times and it snaps = Aluminium. You compensate for that by increasing the cross section. Ooopps what happened between 03 and 04, it got thinner. The back leg thinner by 50%.
The theory is sound but it's not proven (to Aprilia's satisfaction anyway) so for now the purpose of the people on af1 and most other Aprilia sights making a deal over this is for you to make a choice based on what is out there.
What you do with it is up to the individual. As i said for me it was a no brainer. I can't rely on inspection nor can a dealer because there appears to be no pre failure signs and at £40 even if it's all a red herring it's not a biggy to me considering the consequences of a failure should the worst happen.