Say I'm in a TS with you. We're fighting another gang, and we don't have hexes so we don't know who is who. So, I see a guy, and I don't know if it's you, or the enemy gang. So I say vault or jump check. If you vault or jump, you heard me say vault or jump in the ts, so I know the unidentified person is you. If the unidentified person doesn't vault or jump, they didn't hear me say vault/jump check in the TS, so it can't be you.