Unfortunately, Linden Lab has added another level to this, as you mentioned in an earlier post (I'll link it below). Since complying with the new rules laid out in the Second Life Brand Center is now required as part of the Second Life Terms of Service, Linden Lab can ban your hide (and probably thus destroy your business) if they don't think you're following their rules -- even if US trademark law says you're in the right.

Of course, Linden Lab had already reserved the right to lay down the banhammer for any and all reasons, but adding a specific clause about branding to the ToS is certainly enough to justify bloggers' concerns that Linden Lab intends to actually make a move to enforce this.

Here's the "earlier post" I refer to above: http://www.massively.com/2008/03/31/linden-labs-laundry-list-of-legalese-terms-of-service-versus-f/