AHA!!!
I could be of some use!
I manage a local authority youth service, so can offer a prof' point of view on the taking of knives into a youth club.
It's a bit anal, but... what ever an adult does in a youth club sets an example. Everything you say or do has the potential for lodging into a young person's head and affecting how they think. So, you need to take care.
I would not allow staff or visitors to take a knife, pen knife or otherwise, into a youth club unless they a) had a very good reason and b) understood the implications and the need to address these directly with young people.
So, if you are doing a knife safety course as part of a bushcraft session, take a knife. If you are discussing the dangers of knives and young people, you may want to take several knives to show how dangerous and stupid they are as weapons. If you are fixing some remote control cars, you would be better off taking proper tools. If you are fixing bikes, take a bike tool.
The problem comes with people "role modeling" that just having a knife around is OK. It isn't OK for the vast majority of young peple in this country. They will get into shed loads of trouble if they take them into schools (I am also a school govenor), they will get into trouble with the police (locking blade or not), and they will potentially get into trouble with other young people ( young people are MUCH more likely to be a victim of crime than any other group in society).
If you do have a reason to have a knife in a youth club (and I keep my SAK on me, as I manage several buildings and find I usually have to fix something) then be ready to explain why it's ok, and also seriously discourage others from having a knife around.
If your youth group meets on a school site, get written permission from the head master / mistress. I also advise the police.
I would discourage the practise of asking young people to bring knives into a project. Amongst other things they may tell their mates, who then think it's OK to carry knives to your project. Also, any incident relating to the knife will bounce back on you.
Hope that was usefull
Would make a change
Paul
(not Rambo)