IANAL, but it seems to me that if the unit failed, then it's CCH's fault, not the climber who passed on the used cam. Unless the latter knows that that particular unit has a bad braze, I just don't see a liability issue there.
True, but here is where this becomes an interesting legal issue. It can be argued that almost any climber should be well aware by now that CCH brazing is suspect and that the flaw cannot be detected until it fails. So, if you sell a cam to someone and tell them about all the CCH issues, there should be no valid claim. But if you sell them a unit and DO NOT make a disclaimer about the potential for bad brazing (and perhaps the other issues), I bet a good lawyer would find a sympathetic jury pool. I would think the onus would be on you to prove you did not know about the issue.
OTOH, I still run into climber's who have no idea about the manufacturing and QA/QC issues with CCH.
TS