Not an EE either but with an unknown black box connected there has to be more of a chance of some kind of micro vampire draw than there is without the cable connected
Also when not connected there is no risk of dropping it just right enough to shove the connector in harder and break it internally. Has happened to me, got laptop with foot preventing screen/etc damage but the powee adapter was at hust the right spot to hit hard and broke the connector where it attached to the pcb etc
fwiw Dell and their nbdos warranty rock
