You don't want LL to come in and regulate copying in any form. This would be a HUGE mess with farther reaching consequences than you think.

First off, as far as I know it's about impossible to determine if someone has "copied" your work or simply made their own version of it unless one can see prims and/or scripts created by you in it.

Second, most of SL's content is essentially a rip off anyway. Other than sex junk the biggest sellers I have seen in SL are things like Star Wars and Naruto stuff. It's obviously not made or approved by the companies that own rights to these properties and yet it keeps on keepin on.

If LL got involved in monitoring the originality of content in SL then we would have little left to do. They've proven themselves to be heavy-handed with their decisions without fully understanding what the whole situation even is. There's also the fact that they are hard to work with or get responses from as mentioned above.

LL realizes this which is why they try to keep as uninvolved in the commercial aspect of SL as possible.

I think it should stay that way.

The risk of copying is inherent to all commerce and creativity. The best thing to do is adopt a business model that would minimize the impact of copied material getting out and/or keeping a creative edge that would make it hard for others to copy successfully.