If somebody has made up his mind about using a knife as a weapon - telling him about all the risks, disadvantages and viable alternatives I believe is mostly a waste of time. That decision is irrational, it is emotional - so you just can not talk the way out using rational arguments.
But what is probably worth doing - is to advise to look for the answers in the forum. After all, the same topic about knife for SD comes up here every week. The last one with very similar requirements was just a few days ago - about SD knife to take for jogging. Small, light, of course nice and so usefull for untrained person to defend himself/herself against bad guys...
That is not cool, just boring. All the same staff gets told time after time after time...
It's not a knife for me, but yes, my mind is made up and I carry what I please.
Sounds like the arguments anti-gun groups use. :barf: