Linden Lab Official:Permanent account bans
From Second Life Wiki
Per the Second Life Terms of Service:
2.6 Linden Lab may suspend or terminate your account at any time, without refund or obligation to you. Linden Lab has the right at any time for any reason or no reason to suspend or terminate your Account, terminate this Agreement, and/or refuse any and all current or future use of the Service without notice or liability to you. In the event that Linden Lab suspends or terminates your Account or this Agreement, you understand and agree that you shall receive no refund or exchange for any unused time on a subscription, any license or subscription fees, any content or data associated with your Account, or for anything else.
The Second Life Terms of Service are subject to change.