Personally I wouldn't but it would depend on the kid. As a kid growing up with a stutter since about 9 years old I thought I was alone. I never knew anyone who had a stutter till I was 18 (well aside from a speech therapist I saw for a short period in 8th grade) and was put in a speech therapy session with a girl who had a severe stutter. She had a pretty rough story about how she started stuttering. Had her tonsils removed as a kid and when she woke up she had a stutter, as she told it. All those years I thought I was weird for not being able to talk and no one else was like me. If I had met an adult with a stutter I would have felt so relieved I was not alone. Others though, as some commenters have stated, might feel embarrassed with their stutter being pointed out and become even more withdrawn.