Integrity checking is an important concern in many activities, such as logistic, telecommunication or even day to day tasks such as checking for someone missing in a group. While the computing and telecommunication worlds commonly use digital integrity checking, many activities from the real world do not beneficiate from automatic mechanisms for ensuring integrity. RFID technology offer promising perspectives for this problem, but also raises strong privacy concerns as they are usually based on global identification and tracking. In this paper we present an alternative approach, Ubi-Check, based on the concept of coupled physical objects which enable integrity checking relying only on local interactions, without the support of a global information system.