I really can't understand what's so difficult about letting someone who presumably knows what they're doing accomplish the oh-so-easy task of assembling gear. It ain't rocket science. Rebreathers, I can understand. The absorbent has to be packed just right, etc. And I can understand new divers wanting to gain the experience and being paranoid that it's done right because they're not really so sure themselves. But it makes me scratch my head to see divers who profess to have thousands of dives insisting that they're the only ones to assemble their own gear, just because.
[...]what are you afraid of?