Back when I was in high school, '82-'86, I carried a SAK. The swisschamp which is no longer marketed or under a new name. In '84 I got a "superswisschamp", which is now the swisschamp model. If you decide to carry a SAK, I'd say get one of these even if they are on the big side. Should slip right into your watch pocket;) assuming its ok for you to do so. I had teachers that never batted an eye, others I knew better than to pull it out in front of. We didn't have a "zero-tolerance/zero-intellegence" policy, but I still didn't feel it worth the risk. This was in New Jersey, in a more suburban/rual area so there there was a little more understanding.
If you can't or decide against it id say the EMT shears will go a long way to acheiving your cutting goals. IIRC there is a member here who carries a set as her only sharp. Bandanas/hankies may slip easier under the radar than dust masks as someone else mentioned.
Other than that it looks like overkill at a minimal weight-good thing Jace

-Bill Liptak