I would be concerned about slippage,
No they can't slip; theres two cables, one from left/rear to right/front the other from right/rear to left/front.

Basically, if say, the left side moves forward, it pulls on the cable which pull the right side forward it the right side moves it pulls the left side.

As long as the cable tension is maintained (e.g. by a spring) the gantry cannot twist or 'rack'.