My niece asks me to make her something whenever she sees me knit. She's pretty much the only one to have asked for something, besides my other nephews and nieces who asked for blankets, but understand they won't get them right away. I've also became her favorite aunt after I started six months ago, and I'm going to teach her how to knit soon.
I haven't had someone try on something I've knitted that's for myself. At least, not yet. Then again, I'm tiny so it probably wouldn't fit many people anyway.
I knit to my body shape and my size and no one else's. This way no one can steal anything I've knitted for myself. And if I'm knitting for them, I do the same thing. I make sure it's custom fit.