i will preface this by saying that there's almost no chance i would do this, but i'm interested in the discussion and curious what someone who knows more about the design and construction of carbon bicycle components would say, other than the knee jerk "DO NOT EVER DO THIS YOU IDIOT."
i have a one piece carbon bar stem (scott/syncros creston sl ic) on an electric road bike. it has a very sturdy two bolt accessory mount - unlike the very, very light roval alpinist bars on my other bike, which use one hold and worry me a bit with heavier computer/phone mounted.
i use this bike as a commuter, and it's winter, so i've made a custom mount that has a battery powered light hanging from the bottom, centered under the holes. the light is removable for charging, it works well. but it's silly to ride around with a 230wh battery inside the bike and a separate battery powered light adding weight and bulk and needing charging. so, i'd love to wire a light to the internal battery. there's a wire for that. there's an easy route from the internal battery to the interior of the bars. there is no additional hole in that area.
so, three options : 1, leave it as is, don't die. 2, revise my mount to only use ONE of the screws, and probably some VHB tape over a reasonably large surface area including the entire area between and around the holes, and pass a wire through one of the holes. 3, drill a hole using the right drill bit between the holes, gob some epoxy around the edges etc.
i don't design bikes or bike parts but the things i do design often would have reinforcing along the blue lines i doodled there (not my picture, same cockpit.) what are the odds that it's not like this, that all the reinforcing and important fibers go completely around the two-hole area, and i could drill a small hole between the holes with zero risk of assplosion?
badIdea.jpg :
