Wireless Access in Vehicular Environment (WAVE) is finally becoming reality as its mandated deployment on new light vehicles is expected to start before 2020. However, we still have a security issue that is not addressed by WAVE standards: message content plausibility. The issue is that we cannot trust the content of received safety messages, because an attacker may have forged false values in it in order to cause unsafe response from the receiving vehicles. There exist solution approaches based on sensor fusion, behavior analysis and communication constraint check, but none of these completely solve the problem. This paper proposes a communication-based checking scheme that uses low-power transmission of vehicle identifiers to invalidate remote roadside attackers. Built entirely on the WAVE framework, it can be used even when the traditional sensor fusion-based or behavior-based check is unapplicable. We demonstrate the value of the proposed approach in a remote false message attack situation. The proposed approach does not require additional hardware functionality, and only marginally increases the channel utilization.