Carry a bigger blade. In 'sconsin, it don't matter how many inches of blade you're carrying.
If you're carrying something and it's stated purpose is that it is a self-defense weapon - you're breaking the law.
But to answer your original question, a 2" blade is easier to conceal, so that's good. But some people may worry that 2" isn't enough to hit vital organs. Well, that only matters if you know where to aim - I mean a 4" blade isn't going to be much better if you aim for the left ventricle and miss right?
You'll need to rethink what your goals are regarding carrying a 2" blade for self-defense and develop your technique around that:
If your goal is to "run away to live to fight another day" (which is a good goal BTW), realize that you'll be using that knife on another person only enough to facilitate a safe escape. And since you'll only be using that 2" knife when someone's got their hand or hands on you - practice proven and effective countermeasures (which means obtaining some training, or at least some books or tapes), or if that's an impossible thing to do given our crazy hectic schedules - go for the easy way out - hitting the eyes and/or scaling.
What's scaling you may ask? Picture some guy with his hand on your throat. Now take your 2" blade and begin filleting the top muscle off of his forearm starting at the wrist and working your way towards the elbow with a purposeful side-to-side cutting motion. At some juncture during this conflict, your adversary may look at you with an astonished/horrified look on his face - at this point, remember to smile at him.
If you survive that, then you might be able to find the time to fit in some seminars on self-defense I'm thinking! HTH!