By the time one is flying airliners one shouldn't need "training" to check such items
For some this time comes pretty early. And from other posts there emerges an image of crews that tend to just go through the motions, like "XXX Checklist pls" "BLABLABLA" "CHECKED" "BLABLABLA" "SET" "CHECKLIST COMPLETE". Added items could have saved this crew and a few others, but I'd assume that it's rather philosophy of training that's important (know, sounds kinda pompous).