I don't think it'll work.

I don't know your audience, but I've been in similiar situations. On the surface, it looks like a "use" argument... "Why would you need to carry a knife?". But it's not. There's almost always a deeper objection. Figure out what it is, and address that. Some people are afraid of knives. Some people associate a knife with a certain personality type, and assume anyone carrying a knife must either be like that, or is trying to be like that (what are you, Rambo or something)? Some regard the knife carrier as less mature or less civilized. Too often "Guy Thing" seems to mean "immature".

You know what another "guy thing" is? The ability to ignore anyone and everyone regarding any particular issue. <img src="/images/graemlins/smile.gif" alt="" />

That said, I use my knife a lot. Cut open packages, bags, etc. Mail opener. Remove frayed threads. Slice my sandwich. Cut my steak. Cut up cardboard boxes before trashing them. Lots of day to day things. I like the positive reinforcement I get from taking the time and effort to learn how to hand sharpen my knife. The sharper I can get it, the easier and more enjoyable each of these tasks become.