Technical Roof Rail Corrosion

[Cookecarey]

My Dynamic MJ, registered new to me in September 2010 and which otherwise has been a little gem, has factory fitted Roof Rails. Yesterday while washing the car I found some bubbling and /flaking of the matt chrome finish near the front joint with the black plastic bracket, on the Nearside rail, and similar, but less corrosion on the rear Offside roof rail. I suspect defectve materials.
As the car is only at the start of its 3rd year of warranty,I have booked it in for Thursday AM, with the dealer, to have it inspected.
Has anyone else experienced a similar defect within or outside the warranty,
If so, what was the outcome?

 

[Most Easterly Pandas]

Can't say I've had it with the Panda bars, but have with fiat roof rack on my Stilo, although that was fitted 24/7, something which it never was designed to be.

It didn't rust, more the paint coating (silver on these) peeled off.

If rust it's unlikely to be covered, but if a paint defect then it might be

 

[Cookecarey]

Thanks MEP, I believe that the rails are Aluminum, the coating is sort of matt silver Chrome, I could be wrong but I don't think that it is paint, looks more like plating.

 

[Most Easterly Pandas]

Think I'd agree its more plating - my poor description

 

[Cookecarey]

Roof rails inspected as per the above, last Tuesday. I was told that at this stage it may be a 'Goodwill' matter, but that they would pursue it.
Today I had a call from the dealership, Both roof rails will be replaced under warranty. Result!
The dealership Bristol Street Motors,Worcester, have come up trumps, yet again.

 

[Cookecarey]

New roof rails fitted last week by Bristol Street Motors. Under 'Warranty', not 'Goodwill'.
The matt chrome plated finish seems, if anything, smoother that those that were replaced.
Now, how should I best protect the finish?