A yield sign is only for one person, not both. The one with the sign looks out for the other person. The one without the sign just goes, unless he sees the other person is DISOBEYING the yield sign, and he needs to try to stop so they don't smack into each other. Whoever the guys were who got everyone around here doing the yield signs wrong, you screwed up! Unwritten rules of the road are ok if there's not a sign posted (which has force of law).