There are a lot of factors that go into this. If the person is my significant other and a known sketcher, I won't have a problem with drawings. I actually think it might be cute.
Now, if this is a stranger or significant other going out of their way to draw me, I get a little iffy on the subject. I'm not going to hang a picture of myself on my wall, but I can appreciate the gesture from someone I love. Other than that, the actual drawing itself will be kept out of sight since that seems a bit creepy.
If he is super handsome and charming I might think I've scored but if he is all the opposite I think I will feel stalked. Doesn't sound deep but if you're honest with yourself you will probably feel the same way.
Now if you saw a strange on the street and he wanted to make a sketch of you and it turned out to look very good would you still be creeped out that a stranger did a drawing of you? What about caricatures you see people doing at carnivals or party type events?