Damn, does anyone not check out Sony's website anymore?
Here's a link to their warranty policy and service policy on the PS3:
http://www.us.playstation.com/Support/Warranties/PS3
Specifically of note:
[quote name='From PS3 warranty page']
Service policy
You understand and acknowledge that any time SCEA services your PS3™ system (either within the Warranty Period or under a separate service arrangement), it may become necessary for SCEA to provide certain services to your PS3™ system to ensure it is functioning properly in accordance with SCEA guidelines. Such services may include the installation of the latest software or firmware updates, or service or replacement of the PS3™ hard disk or the PS3™ system with a new or refurbished product.
You acknowledge and agree that some services may change your current settings, cause a removal of cosmetic stickers or system skins, cause a loss of data or content, or cause some loss of functionality. You should back up your hard disk regularly to prevent loss or alteration of data, although some content cannot be backed up and must be reinstalled by the user. You should also remove any peripherals, non-PS3™ system components, and any content that you consider proprietary, private, or confidential before you send in your PS3™ system for service. SCEA shall not be liable for damages resulting from your failure to comply with the foregoing, or any instructions provided to you by SCEA. SCEA reserves the right to refuse service or void the warranty of any PS3™ system that has been modified or tampered with.
Except as otherwise stated in the Limited Hardware Warranty and Liability above, you agree that (i) the services are provided "AS IS" without any express or implied warranties; and (ii) SCEA shall not be liable for any direct and indirect, consequential, or special damages, including any damages that may arise from loss of data or functionality. The foregoing limitation shall apply to the extent permitted by applicable law.[/quote]
Bolded points for the curious. Which states that in the repair process they may change your settings, remove any system skins/stickers, format your hard drive or send you back a system with lesser functionality than you sent in. That, and you can't sue them/complain about it if they send you a system with lesser functionality.
Which means if you send them a 20GB/60GB system, you might end up with a SW-only BC-capable system or a non-BC-capable system. Chances are slim that they would do that, though it's in their service policy that they could. I've never heard of anyone sending in a 60GB and getting back an 80GB/SW-type BC system board in it, or a 80GB/no-BC system board in it, though it doesn't mean it couldn't happen.
Just some FYI for people worried about it.