If you have a router that supports access restrictions for specific devices, you might be able to configure it to disallow internet access only for your specific PS3 (eg. by using the PS3's IP or MAC address).

You may also be able to block a specific domain (playstation.net) by setting up parental controls on the router. These features aren't available on all routers.

Another option is to manually specify a fake DNS server in the PS3's network config so that your PS3 is unable to contact playstation.net.

For example, set your PS3's DNS server to 127.0.0.1 which is a local loopback IP. Anything 127.x.x.x will not go out onto the network at all, much less onto the internet.

Yet another option is the proxy method. You can set up a real proxy and block playstation.net or simply specify a fake local IP for the proxy.

Lastly, you could set up a separate private network between the PC and PS3. This could be as simple as a crossover network cable which between the two machines, or more complex with another router that isn't connected to the internet.

All the options except for the first and last will expose your PS3 to the internet.

I consider all options safe from banning since no information is passed to Sony in any of the cases and they should have no interest in you if you're not messing with their network.

That said, it's up to you to use whichever method you feel safest and most comfortable with.

--- UPDATE 1- updated with better (but slightly more risky) blocklist to allow ps3 game updates via Multiman.
---UPDATE 2 - added OpenDNS list - UNTESTED!

This guide will let you keep full Internet access (except PSN, of course) on your PS3 without letting Sony collect any data. Note that you must have a router that supports DD-WRT (UPDATE - or be willing to use OpenDNS) for this to work.

1. Install dd-wrt ([url]www.dd-wrt.com[/url] | Unleash Your Router) on your router if you haven't already. This is fairly complicated so you will have to follow the instructions on the dd-wrt site.

2. be sure you set your PS3 DNS server to your router's IP address (usually 192.168.0.1) and not your ISP's

3. Log into your router and click on Services and then scroll down to dnsmasq

4. be sure both dnsmasq and local dns are enabled.

5. add the following lines and then apply/save your settings

address=/.playstation.net/127.0.0.1
address=/playstation.net/127.0.0.1

6. click on the setup tab and be sure the following items are checked: use dnsmasq for dhcp, use dnsmasq for dns, and dhcp-authoritative.

7. turn off your ps3 and turn it back on.

8. to test it go to online manuals on your ps3 and if you get an error then it is working

9. have fun

UPDATE - if you want to keep PSN game updates working you can try using this list instead. Note that using this list is slightly more risky as I might not have gotten all of the servers they use but they do send the data they collect to *.np.community.playstation.net so blocking that and the auth server should do it. Still, you might wish to restore default settings (not reformat, just reset/restore the settings) to clear out your PSN login info if you use this method.

--- DD-WRT List
address=/auth.np.ac.playstation.net/127.0.0.1
address=/.np.stun.playstation.net/127.0.0.1
address=/ena.net.playstation.net/127.0.0.1
address=/.ena.net.playstation.net/127.0.0.1
address=/.ps3.update.playstation.net/127.0.0.1
address=/service.playstation.net/127.0.0.1
address=/.service.playstation.net/127.0.0.1
address=/creepo.ww.hl.playstation.net/127.0.0.1
address=/.creepo.ww.hl.playstation.net/127.0.0.1
address=/.np.community.playstation.net/127.0.0.1
address=/np.community.playstation.net/127.0.0.1
address=/manuals.playstation.net/127.0.0.1


-- OpenDNS List
auth.np.ac.playstation.net
np.stun.playstation.net
ena.net.playstation.net
ps3.update.playstation.net
service.playstation.net
creepo.ww.hl.playstation.net
np.community.playstation.net
manuals.playstation.net