Front Derailer mount on P2C - Problems.

It seems that the rivet holding the mounting bracket for the front derailer is starting to pull slightly away from the seat tube on my 2008 Cervelo P2C.

I took it into my LBS to look at it and the mechanic wanted a more senior mechanic to look at it since there is some concern.

Anyone else have this problem and how was it fixed?

I was told that one mechanic like to shoot from the hip and fix things in house and the other mechanic is much more methodical and like to do things right and would not hesitate to send it to Cervelo if he has to.

I told them to use the SECOND mechanic.  I would hate to be without my bike for a long time plus the expense of shipping, but I want it done correctly even if Cervelo has to do it.

Any knowledge on the subject would be appreciated...