a support bracket mountable onto a bottom portion of the cable-operated door, the support bracket comprising:

at least one hole for receiving each a corresponding fastener for securely mounting the support bracket onto the cable-operated door; and

a connection point onto which an extremity of the tensioned cable is connected;

a guiding assembly operatively mounted onto the support bracket for travelling along the inner portion of the fixed structure so as to guide the movement of the cable-operated door along said fixed structure when the support bracket is mounted onto the bottom portion of the cable-operated door;

a braking assembly operatively mounted onto the support bracket for cooperating with the tensioned cable, the braking assembly comprising a swivel component pivotably mounted and movable about the support bracket, the swivel component having opposite first and second ends, the first end being provided with a braking arm, and the second end being provided with a lever portion positioned, shaped and sized about the support bracket for cooperating with the tensioned cable, the braking arm projecting out from the support bracket for positioning of said braking arm adjacent to the outer portion of the fixed structure, the braking arm being operable between a retracted configuration, where the braking arm is urged away from the fixed structure via a frictional engagement of the tensioned cable against the lever portion opposite to the braking arm on the swivel component, so as to allow the guiding assembly to guide the cable-operated door freely along the fixed structure, and an engaged configuration, caused by a given loss of tension in the cable resulting in a decrease of frictional engagement of the cable with the lever portion, where the braking arm is no longer urged away and thereby engages a portion of the outer portion of the fixed structure for braking movement of the cable-operated door with respect to the fixed structure;

biasing means operatively connected between the support bracket and the braking assembly for biasing the braking arm into an engaged configuration; and

a guiding channel defined within the lever portion of the swivel component for guiding the tensioned cable about the braking assembly and onto the connection point of the support bracket;

the improvement wherein the brake device is provided with an anti-theft mechanism comprising:

a catcher assembly operatively connectable to the fixed structure, the catcher assembly comprising a component removably mountable onto the outer portion of the fixed structure via at least one fastener; and

a protrusion operatively projecting from the braking arm, the protrusion been shaped, positioned and sized with respect to the catcher assembly so as to be engaged with said catcher assembly when the braking arm is operated into the engaged configuration caused by a given loss of tension in the cable, thereby preventing the cable-operated door from being displaced upwardly along the fixed structure as a result of the catcher assembly abutting against the protrusion of the braking arm.