My 2006 2551 has probably the same awning made by Fiamma. As you say, when you retract it it snaps into the locked position in which the awning is completely boxed so the "microburst" can't reach the fabric. That being said, I suspect this is one on the thousands of products that fulfull a need that doesn't really exist, but is sold on the basis of fear of a catastrophe. I, too, have never seen an unfurled awning except a stationary one in a campground when the owner didn 't store it even though storm warnings were being given on TV. Maybe I'll eat my words wrapped in my awning some day, but I don't feel a need for this gadget.
