Why did the alarm was set off? Do these locks work only with a key that passes through electricity or have some other built-in secondary check? Really curious.
Apparently there are parts of the Santa Clara County jail that are very old. This occurred in a dorm-style housing unit, and the key he made opened a stairwell door (the door to the stairwell being inside the housing unit, which is how he was able to repeatedly test without scrutiny). The door was alarmed and went off when it opened. Most modern jails don't use skeleton-style keys, and the doors are opened and closed electronically, but the part of the jail he was in was decades old.
I'm not entirely sure, but I think that the door was not ordinarily used by anyone, something akin to the jail version of a fire exit. I believe it was set to alarm regardless of who opened it, but if an authorized person opened it, presumably they would let whomever receives the alarms know about it in advance and not send in an army of officers.
Presumably they disable the alarms before the guards open the doors, and enable the alarms when the prisoners are unsupervised. Like how you enable your house alarm when you leave, and then disable it when you return home.
