Best practise is to keep outlines below 1900 nodes so the next mapper does not quickly walk into the 2000 nodes wall if something changes to such a large area object. Yours of 1900 and greater are being highlighted as a future maintenance problem. Yes you can map cutlines as areas, but why would you when the man_made=cutlines is available for anything cutting through wood and scrub like ski pistes, lifts and powerlines. Apply best practises and no one will disturb you.

Happy mapping..