I have removed the cliff, as satellite imagery seems to agree. While it looks steep, there aren't any visible drops or cliffs. I assume (as the outline was drawn 13 years ago and only slightly modified since then) that is was merely a 'this is steep' and not a 'there is an impassable cliff here'. 
I think someone who descended this side is a reliable source to delete it. While I could have only deleted a part of the line, it felt like cherry-picking, because now, as it is, the entire cliff should be called into question. Rather have visible missing info than wrong data that looks real. 
WIll leave this note open for discussion.