for me, the inside trunk latch is an idiotic invention. i bought a 2004 xgl 350, because it was about the only "new" car that any dealer could find, such that it could be disabled.
the purpose of a trunk is to have a separate compartment for storage, that can not be accessed from inside the car.
in other words, someone cant get into the trunk, by merely breaking a window, or otherwise getting into the cab.
having an inside trunk latch that can not be disabled, or back seats that can be folded down, defeats the purpose of a trunk.
it is the one and only reason why i got this car. most any other car would have been fine for driving purposes, for me.
the xg has a switch at the trunk lock that disables the remote and the inside trunk latch from opening the trunk (i.e only the master key can then open the trunk). and then it has buttons accessible from only inside the trunk, that disables the back seats from being folded down from inside the car - thereby having a trunk work like a trunk, again.
the sub-key, or parking attendant key, does not open the trunk - so it could be given to your repair guy.