In an aspect, a method of preventing tampering of a mobile device lock, wherein the method comprises: a client application executed in a mobile device monitoring the reception of presence messages transmitted, e.g. broadcast, by a user-detecting device in the vehicle, the user-detecting device comprising a radio interface configured to wirelessly transmit presence messages when the vehicle is moving, preferably the presence message comprising an identification code, preferably a MAC address, of the user detecting device. The client application repeatedly, for example periodically or regularly, wirelessly transmitting notification messages to a server in a network, the notification messages signaling the server that the client application is being executed on the mobile device. The client application determines if the user is inside the vehicle; monitors the velocity of the vehicle and locks the mobile device; and monitors user interaction with the mobile device.