Is it ok to give a sketch artist feedback if something looks off?

[Vargaman]

Hi all,

So I was wondering, since we have some artists on the forum, would you (as an artist) appreciate if someone gave honest feedback?

For example, I know we've all seen some crazy detailed sketches of faces, but maybe the eyes are just off or the face is too long for the subject and you notice a pattern of it. But it's like other than one small feature everything looks amazing, but it's just glaring and stands out.

Should you say something to the artist in a positive, constructive way? Perhaps they don't see it, or no one has ever said something so they keep doing it? It's kind of like telling someone there's something in their teeth. It's awkward to do, but most of the time they'd thank you.

I have an example in mind, but don't want to post yet since I'd like some feedback first before sharing the sketch.