A friend of mine has already broken two arm rest covers for his Audi RS4, at over $200 a pop.  They snap into holes in the underlying structure, so they are weakened in order to allow the two arms to give a little during installation.  The weakened section is where they always break.

This is what the part looks like, upside down, from the side:

In this flash photo, you can see the hollowed out section along the top; note the rear arm had to be glued back together again after it broke:

This shows the arm rest cover along with the printed part which will go in between the arms, to reinforce them:

And, finally, the arm rest cover with the reinforcing part in place: