Any question answered...

They are indeed but be careful. When you stop at the lights don't dismount and lean back on the tip of your saddle. The last 4 pairs of Assos shorts I had now have a slightly transparent piece of lycra through which any wheel sucker has the joy of seeing the top of my arse crack.

I have this too, and am getting it on my latest pair too. But I don't lean back on the tip of my saddle.
I am still clueless to the cause, and have been tripley carefuly with my current pair (doubley careful with the pair before that), and they're still showing signs of going. only get about a year out of them :/