These sysvals would let know the game if the player one or two are carrying an object. I know with npcs there's a target function that lets know the game if that npc in specific is being carried, however, I'm suggesting a sysval to not have to apply an script to all carryable objects an optimize the scripts.
These sysvals would be Read-Only.
Also, what about another system variables (Readable and Writable) that let's or no the player carry objects? I'd be convenient for player's customization, or if you want the player can't be able to carry objects while it's doing certain action