The real isue isn't whether the carriage can be lowered with or without the key on, but rather just how unsafe that entire precedure would be.

We've all seen how unpredictable failures can be. Although it's not likely, a hose can break, a hyd packing can fail. I've presonally seen a tire tube fail while the truck was sitting, no operator present, not running. Sounded like a shot gun blast- scared the sh** out of me- the point is- you never know.