For hifi systems (stereo or Home theater), as long as all the speakers are wired the same way, it doesn't matter .... all of the speakers will be in the same phase.
You are referring to what is called relative phase, which means that the connections assure that both speakers are moving in the same direction at the same time. If relative phase were to be incorrect, the symptoms would be extreme and obvious -- vague diffuse images, poor bass, etc.
The original poster is referring to what is called absolute phase, which refers to the outputs of BOTH channels being inverted in phase with respect to the program source. That will have sonic effects which are subtle, but will definitely be audible to some people listening to some recordings on some systems. Particularly on sharp transients, where the leading edge will have the wrong polarity (the ear being particular sensitive to the leading edge of transient waveforms, compared to what follows during the next fraction of a second).
An inversion of absolute phase in a preamp or power amp can and should be corrected by reversing the positive and negative speaker leads on both channels. It would be more problematical if the inversion were in a source component, because correcting it for that component would create a similar problem for the other source components.
Regards,
-- Al