can't blame them. even when i was a mechanic, i was nervous the first couple times i actually removed an airbag. there's a hell of a lot of energy in them, so you do have to be careful. but since you won't be removing them or even disconnecting them from the car for this, it's pretty safe. just don't hit any of the impact sensors inside the doors while the key is on.
when i was installing DVDs i never removed the headliner either - just A and B pillar trims to allow access into the headliner. less dis/re-assembly than running along the lower sills.
if you have a pano-roof, you might actually be lucky in that you can simply pull off the trim securing the headliner along the edges of the sunroof opening, then just tuck your wires in that way - far from the airbags and above the sunroof's moving parts/tracks. then you won't have to mess with removing ANY pillar trim.
as for preventing wire rattles, you can either zip-tie it to existing wiring or wrap the wire in foam or felt tape so it can't rattle against anything. most times, though, the headliner itself already has padding for noise reduction, so there's already padding to prevent rattles. obviously, every car is different - i can't say what yours may be like. but in most vehicles with a sunroof, there's an easily removable (no tools required) trim around the edge of the sunroof opening that simply pushes on, just like the weatherstrip around the door or trunk. worth a look - might save you a ton of time and effort!
