I do not think carbon expands and contracts with temperature change. That is one of the reasons people have switched to carbon from aluminum. However, water does expand and contract and if moisture gets into the fibers in any way it can start to cause cracks in the shaft. Each freeze thaw cycle can increase the size of the cracks. As JeffB states the aluminum insert will do the same. Depending on how many times you shot the arrows I wouldn't recommend shooting them.

Even if you did look at the outside of the shaft and it looks fine the shaft can be damaged from the inside out at the insert.

I have found arrows over a year later after shooting a deer. They generally turn brittle some. Got to remember, they are held together with epoxy and layers of wrapped carbon. If you can sit there and bend them over your knee to extremes and nothing happens, then they are shootable, but spine has probably changed. I would want to shoot good equipement.

I would shoot them... Maybe not the most educated choice but you asked what we would do so I would shot them....

Well, i've just spent to last 30 minutes attempting to find out the answer to your question... I found an article on bicycle frames and yes I would still shoot the arrows.. The article is long but actually has tons of interesting info on the differences between carbon, aluminum, titamium, and other metals... If you want to check it out an a expample of some of the things discussed below..
http://www.calfeedesign.com/pdf/Calfee_TWP.pdf

[align=left]Comparison of Materials Used in Bicycles[/align][align=left]STEEL [/align][align=left]Pros[/align][align=left]• Inexpensive[/align][align=left]• Strong[/align][align=left]• Stiff[/align][align=left]• Resilient and "lively" fee[/align][align=left]• Easy to work with and repair[/align][align=left]Cons[/align][align=left]• Heavy[/align][align=left]• Corrosive[/align][align=left]• Designs limited by available[/align][align=left]tubes and lugs[/align][align=left]• Brazing and welding produces[/align][align=left]weaker, heat-affected zones[/align][align=left]TITANIUM[/align][align=left]Pros[/align][align=left]• Light[/align][align=left]• Strong[/align][align=left]• Resilient and "lively" feel[/align][align=left]• Shock absorbing[/align][align=left]• Non-corrosive[/align][align=left]Cons[/align][align=left]• Expensive[/align][align=left]• Designs limited by available[/align][align=left]tubes[/align][align=left]• Not easily repaired[/align][align=left]• Bad welds are easily hidden[/align][align=left]• Stiffness is traded off for light[/align][align=left]weight[/align][align=left]ALUMINUM [/align][align=left]Pros[/align][align=left]• Inexpensive[/align][align=left]• Light[/align][align=left]• Adequately strong[/align][align=left]• Very stiff for the weight[/align][align=left]• Non-corrosive in non-salty[/align][align=left]environments[/align][align=left]Cons[/align][align=left]• Fatigue risk requires "overbuilding"[/align][align=left]• Lacks resilience and has "dead"[/align][align=left]feel[/align][align=left]• Not easily repaired[/align][align=left]• Bonded joints prone to failure[/align][align=left]• Heat treatment can be[/align][align=left]inconsistent[/align][align=left]CARBON FIBER[/align][align=left]Pros[/align][align=left]• Lightest[/align][align=left]• Strongest[/align][align=left]• Best shock absorption[/align][align=left]• Unlimited design applications[/align][align=left]• Non-corrosive[/align][align=left]• Material has high fatigue[/align][align=left]resistance[/align][align=left]• Some designs are easily[/align][align=left]repaired[/align][align=left]Cons[/align][align=left]• Expensive[/align][align=left]• Technology still evolving[/align][align=left]• Strength and stiffness are design[/align][align=left]dependent[/align][align=left]• Fully molded styles have very[/align][align=left]limited sizes[/align]

Odom, that's interesting comparison between aluminum and carbon.
I have revaned and inserted new nocks and have shot them a few hundred times and the only arrow that busted on me was when I got a robin hood , my bad. Good stats and thanks for sharing.

Bobby

yeah, I have also and have never had a problem with it so I really don't know what they mean when they say "heat treated"