Does component video switching hurt picture?

Soon to be purchasing HT gear, including receiver and progressive scan dvd player. Does utilizing the component video switching feature in A/V receivers degrade the picture quality? Also, if sending progressive dvd signal, does the switching pass the signal properly?
I have a Ref 30 pre/pro that is capable of comp. video cable switching but I never use it, I did not compare them side by side as I'm convinced that direct video from source to receiver (progressive scan capable monitor) is always going to give me the purest signal. I have both Sony S9000ES and Toshiba SD-9200 connected to my monitor at the same time thru the monitors dual CV inputs so I'm just switching them from the monitors input selector instead of the pre/pro. I'm also using Audioquest YIQ2 CVC which beats out the Monster M1000 CVC and all others I tried.
It's hard to know if video switching will hurt the picture quality, since this may be rather specific to the equipment and the cables you are using. However, you'd probably be on fairly safe ground saying that it doesn't improve the picture quality. As Charles noted above, you increase the chance of retaining good video quality by going directly from the DVD player to the TV monitor.

You might be interested to know that when Bryston designed their high-end SP-1 preamp/processor, they deliberately left out video switching because they found it deteriorates the audio quality. Video switching generates a lot of high frequency interference, so it's not unreasonable to conclude that it affects not only audio, but video as well. When given the choice, it makes sense to keep the signal as pure as possible and eliminate switching wherever possible.
Unless the processor you buy utilizes broadcast quality video switching circuitry (Proceed AVP--for S-video and composite only)then you are losing quality. I owned a B&K Ref-30 for a short span, and the component video switching capability is nice. B&K really tried, since they cut off the on-screen display on the component video outputs, but going through their switcher will still degrade the video quality. Also, I've heard that the current selection of component video switchers available are good for standard definition broadcasts, but if you jump to HDTV you might see a big loss in quality. If your HDTV has enough video inputs, use them directly.