WK, although not privy to the in's and out's of the 345 FCOM - it is of course, superceded by the OM-A... which states that the augmenting crew have a responsibility to participate in the preflight proceedings etc....
I am stunned that there are supposedly professional pilots who take no interest in the calculation and input of critical data.
Disregarding the 'professional' aspect, that augmenting crews will put their blind faith in the operating crew, who are also tired - is beyond me.
Before you get excited about augmenting crew 'interfering' unnecessarily - that's not what I'm talking about - it's waiting until it is clear that the operating crew have missed a safety critical item/issue, and mentioning it in an appropriate manner (probably another separate thread in itself).
Finally, if I was augmenting and was told by the operating Captain to stay out of the cockpit until doors close... we would have some issues to resolve!