Originally posted by h00pz
than ban u via, device id
Exactly. They refer to it as your "PSID" (not to be confused with PSN ID, your login info).
Your PSID is the identifier your PS3 sends out to Sony for them to have absolute authority (think of it as how much power your PC account at school has, and any administrator can slap it away just like that).
When your PS3 gets banned, they ban your PSID, not your MAC Address (similar to how Xbox bans Keyvaults).
edit: And in case anyone was interested, the PS3 hack scene does not have a hack to change this yet, and if they ever did, it might not be very effective (just like 360 KV's only last like 2 hours on a JTAG).