I've seen people go both ways on this, Marksmanship is listed as an Optional skill, but Albedo says "Any enemy with ... the Marksmanship skill" (not "that USES the Marksmanship skill") So if a model with Marksmanship shoots a model with Albedo, can they choose to not use Marksmanship and not suffer the penalty (and also not get the bonus from Marksmanship)?
The current rules don't care if you are using the skill just that you have it so until it's FAQ'd otherwise that's how it works
I will throw some kerosene to this fire... RAW this happens with stuff that has the Reflective property, which is irrelevant for Eclipse (since you can't draw LoF through it). BUUUUT! White noise! Could it be that you can deploy White Noise to negate the use of Marksmanship to the enemy? (They could draw LoF anyways unless they have MSV)...
