...I suppose it could be suggested that if it wasn't kept like a prison camp with lock-up at 9pm and snipers on the watch towers then people could easily walk out rather than having to scale the fences and dig escape tunnels aiming for the nearby woods!
Edit: It'd be interesting if one year someone attempts a bid for freedom on a war time era motorbike jumping over the gate and hedge in a Steve McQueen type stunt. 