tweetymp4,

It is the current delivered by the amplifier that will trip the protection circuit. The amplifier has no means to look down the wire and count the number of bodies connected. As long as the impedance is 4-Ohms or above on both channels, the amplifier will not care about the imbalance. Really, the magnitude of the impedance varies (wildly) with frequency. If one wanted to keep the impedance matched on all channels at all times, on would need to play mono music or never use multichannel amplifiers.