They are covered if they are packed in accordance with AP instructions.

The terms and conditions of Extra Cover make it very clear when an article is accepted and extra cover purchased for that article, it is covered for loss or breakage - it is conditional on a number of things, including that is adequately packaged.  The terms and conditions also indicate very clearly what articles are excluded - and the exclusions do not include fragile goods.

AP are governed by the same consumer and other relevant laws as any other entity when it comes to the terms and conditions of their services and insurances. 

Whilst its "your thread" I will make posts that seek to stop the creation of discussion board furphys as they are very unfair to others who may be misled by them.

I have both sent and received fragile items by AP with extra cover. I would always purchase extra cover if the cost of the goods was more than I was prepared to lose if they were lost or broken in transit.