hornetdt wrote:I guess there is a certain logic behind not continuing the use of that kind of lock. If you think about it, why would you want to know if someone was trying to get through your lock? If they couldn't do it, then your lock is fine, no need to upgrade it. On the other hand, if someone was successful in the defeat of a lock, you will definitely know about it, you don't need a lever to tell you.
Another point of the "detector" technology was that it immobilized the bolt, making picking a pain in the rear end

LSS says that the Detector required a special key to reset the lock (14_1.2.3). Later on, it suggests that a picker could do the same -- "If the tumblers are lifted too high, they will detained or detected in that position, and the operator will have to release them by turning the bit round in the opposite direction before he can begin his work again" (LSS+ v5, Locks and Safes: The Construction of Locks).
It was eventually picked. A.C. Hobbs opened it in 25 minutes at the Great Exhibition of 1851, without disturbing the detector. (LSS+ v5, SS:TCL) LSS seems to suggest that he used the first 2 in 1 pick to do it.
He went on to pick the Bramah lock at that same exhibition.
If you're into lock history, get a copy of LSS+ (the electronic version, not the book). The additional "bonus" materials include two different books on lock and safe history, one written by George Price and the other drawn from the papers of none other than A.C. Hobbs. Both have been updated by Marc Tobias.