by mhole » 13 Jan 2011 9:12
More detail would be helpful here, as exactly which door the lock is fitted to, and whether the individual lives alone is of possible importance.
The snib can be disabled, but you must consider that doing so also removes the option to put the door on the snib when putting out the bins, or getting the post. You may reduce the chance of lock-ins, whilst increasing the risk of lock-outs.
I would suggest replacing the lock with a roller latch. This can (and in fact *must*) be locked from inside with the handle, but cannot be deadlocked so that the key will not open it from outside.
I have always though the option to deadlock a yale from inside is moronic, and it would be so simple to remove this function, whilst retaining the option to lock the latch back.