Since when was being cautious a crime?

Trust is earned, not given away freely. So you are right to not automatically trust someone that you've just met. But it sounds like you take it too far. While you don't have any reason to trust them YET, you also don't have any reason to not trust them. Unless they have broken your trust, you shouldn't have any mistrust toward them. And because you've just met, they can't have broken your trust yet. There's a middle, neutral ground where you don't trust or mistrust someone. THAT is where you should be with people you don't know. You're right to not immediately trust new folks, but you shouldn't go so far in the other direction. THAT is inconsiderate.