switch box degradation?

My father is in the process of having a house built and is having his entertainment room wired for his surround speakers. His current receiver only has two channels of power for surround speakers, and is only stable into a 6-ohm nominal load ( w/ 80W per channel into 8-ohm loads). In order to be somewhat future-proof, he has installed 4 surround speakers (which will work with the new 7.1 surround-side/surround-back formats). To make use of the extra set of surrounds (until my father upgrades to an actual 7.1 system), the electrician/installer is suggesting that he can hook all 4 speakers up to the two surround channels through a switcher box and that there will be a) no damage to the receiver; and b) no sound degradation. Does this sound possible?

It seems to me that the switching box may degrade the signal coming from the two surround channels, and that driving 4 8-ohm speakers in the two channels will drop each channel’s load to 4-ohms, lower than the required 6-ohm minimum. In addition, the two pairs of surrounds will play at the same volume, but will be at different locations relative to the listener (so the resulting perceived volume will be different, and the delay times specified within the receiver based on distance to the listener will be mis-specified, leading to degraded coherency among the rear and side surrounds).

Does anyone have experience with these boxes and how well they perform? Would you suggest leaving one of the pairs idle instead (or manually switching between the two based on movie/music use)? I’m not entirely sure if this electrician/installer has a complete grasp of audio issues, so I wanted to double check!
Felthove- There are switch boxes that will provide a nominal load with additional speakers added in parallel. Is there no degradation? In terms of hi-end audio, of course there is degradation. However, in this application, it won't matter! The amount of degradation is small when taken in context of the compromises in the overall system. Don't sweat it. When the receiver is upgraded, remove the switch box and enjoy. Just my .02
Jctubes: When you say “will provide a nominal load with additional speakers added in parallel” what type of load are you referring to? Won’t the receiver see a 4-ohm load in each channel if each channel is pushing two 8-ohm speakers. Am I missing something or does the box do some kind of impedance adjustment?
I would pull the wires from the two speaker pairs to the location for your receiver (or what ever may replace it later), and choose hook up options after construction. If your father is truly preparing for Dolby 7.1, a new processor and amp will be required for the additional discrete channels.

In Dolby 7.1, the rear speakers are configured very near one another in the center of the rear wall. Playing Dolby 5.1 from these center rears will not help his current system, and may provide too low an impedance for his current amp. Even if the switch box provided his amp with a safe load, the time delays and speaker position will be wrong for his current Dolby processor (as you stated).

The switch box will be not only provide an insertion loss, but also an unnecessary expense along the path toward Dolby 7.1. Waiting until the construction is complete may put him in a position to be able to choose from any number of new Dolby products that will resolve these issues. It's great that you're helping him avoid this unnecessary and possibly damaging expense.