I have on many occasions. Typically my approach is, "hey, I'm a knife geek. What do you have there?" with a smile. I've never had anything less than a friendly response, and yes I have asked some very sketchy looking people.
Then again, I have worked in jobs where I am meeting new people all day, every day, since I was 16 (21 years ago), so maybe I've just developed a way of greeting people that keeps them at ease.
Then again, I have worked in jobs where I am meeting new people all day, every day, since I was 16 (21 years ago), so maybe I've just developed a way of greeting people that keeps them at ease.