That's actually a good point! Forgot about the night naps. Though honestly I haven't noticed any problems while playing on Locker... In fact the black is really nice on the outside. I guess a shade of blue might work if I do need to change it at some pointHuh, black hitmarkers instead of a black kill-confirm marker. That isn't hard to see in some maps like Locker's shadows? The night maps may make you (and me!) want to reconsider black.
I'd say I only really take notice of the kill confirmation (red) and headshot marker (green), anyway