Only down near the bottom, on the "curvy bit", no? Not on the actual "wingletty" bit. Which might be the key - I think the curved bit is still somwhat built-up in the fashion of wing structure, whereas the "wingletty bit" is more CF?
(I stand corrected. Just saw one near the end of a GEX winglet. Hope we had them on during FT because I never noticed them!
Knew I should have double checked some pics).