Preamble: I have been using CF poles in my summer and winter tents for many years, under all sorts of conditions. Prior to that I had been using Easton aluminium poles, again under all sorts of weather. I have seen failures in Easton poles:
I have repaired such breaks with aluminium sleeving - a discarded sardines in tomato sauce can actually:
There is a limit to the amount of curvature you can put in any pole, be it CF or Al (or a stick picked up off the ground). Exceed that limit and the tube will snap. In addition, in the case of Al it is possible to 'work-harden' the tube by repeatedly taking it close to the limit, such that it becomes more brittle. Been there, done that, second picture. There are several solutions to this.
Aluminium poles: PreBend. It is possible to put some curvature into an Easton 7075 T9 pole. When you do this it alters (increases) the amount of curvature that the pole will take before it reaches its limit. This is commonly done at the factory using special equipment, but it has to be done properly or you can wreck the tube. I have seen a skilled shop owner put some curvature into an Easton pole (as a replacement), but doing it by hand is risky. The details of how it works without breaking the tube are ... curious.
CF poles: You can NOT prebend these. You can put elbows into the pole assembly, as I do. Otherwise you must limit the curvature.
There are three different ways to make CF tubes: fabric wrap (Fibraplex and others such as bike frames), pultruded (kite spars such as Avia), and bi-directional wrap (arrow shafts such as Easton Carbon FX and a Korean brand).
Fabric wrap is tolerant but not all that stiff. It may suffer from slight variability, especially if done by hand. Fibraplex used make their tubing by hand (very early days), but I think they have now got some automation involved.
Pultruded is enormously stiff but will fail abruptly and catastrophically with a full-length split. It is not the CF which breaks in this case but the polyester (or epoxy) resin which encases the fibres. That resin is far weaker than the CF fibres.
Bi-Directional wrap is hardest to get as it requires a very large production machine for its manufacture, but it is the best sort in my opinion. Sadly, it is more expensive than the pultruded version.
Even so, it is possible to snap one of these if you load a joint too far, or don't seat the joint properly:
Caution: there are quite a lot of CF arrow shafts on the market which LOOK like bi-directional wrap but which are really a fake. I got burnt by one brand (Rebel 4560) which turned out to be pultruded glass fibre with a film of cosmetic carbon fibre over the outside. It was called 'carbon fibre', but they carefully avoided making an enforceable claim.
I suspect Henry is talking about pultruded tubing? If so, I agree wholeheartedly. But don't dismiss CF tubing when the engineering is done properly.