What would be the chances of the flight crew knowing what cargo was going to be on their flight, far enough ahead of schedule to plan something like that?
In my days in Ops, I would get the cargo manifest a few hours before departure to do the planning. Often it would get bumped to another flight if we had weight and balance (and space) issues. The cargo manifest went to the Cabin Crew. I would only notify the Flight Crew of what cargo was on board if there was a NOTOC involved. Even if we had something unusual, i.e. a car, that we knew about in advance, the crew wouldn't know until they saw it on the ramp.
I have no idea what load-control system you used to work with, but from my days doing weight & balance (4 years ago), I used to work with several different systems, all of them creating a NOTOC and an indication in the loadsheet (in the LDM section) when valuables where onboard (VAL/xxx/hold). It's something pretty usual in Switzerland, to have valuables onboard, so I'm used to print NOTOCs and loadsheets with that code...