Whether or not input shorting plugs make a difference will depend on the design of the preamp circuit involved. It is possible that a few models could pick up some noise though an un-shorted input and pass it to the input in use.
However, I'd think that a fairly rare situation and, to me, would indicate poor design choices for that one issue. It should not make a sonic difference with most equipment.
However, I'd think that a fairly rare situation and, to me, would indicate poor design choices for that one issue. It should not make a sonic difference with most equipment.