To avoid leaving things in sight in the cabin, most cautious owners will, of course, put any valuables in the boot.
The problem with this on the modern Falcons and other cars is once they break a window and open the door, they can easily get into the boot by folding the 60/40 split seats forward.
I've often thought about installing a lock that allows you to lock the seats in place (Locking from the rear of the back uprights of the seats from the boot), to add another layer of protection.
I reckon it could simply be done by anchoring two chains from the child restraint bolt below the parcel shelf and then to eyelet bolts anchoring the chain in the back steel frame of the seats by padlocks.
Hmm... Maybe my next mod.
