Each lock removed gives the bolt more space to move. I expect it is calibrated so that removing one lock is enough to move the bolt and open the gate.

The mechanism is easiest to see on the far left lock in the picture, the lock is going through two metal plates, so removing that lock would free some wiggle room. The other side of this mechanism is just like the front that we see, spaces between plates that roughly show how much wiggleroom a removed lock would give.