When is it inspiration vs. theft of design?

The recent sofa chronicles on this blog are fascinating. It has stirred up all kinds of middle class striver anxiety about "authenticity".

The debate seems to be that a guy here in Seattle will make a sofa from any photo you bring him. Custom work. A few commenters think he's just a rip off artist. Maybe he is, but is that bad? And how much ripping-off can one really do of Restoration Hardware when their own designs aren't that original?

On the rip-off artist charge, does this mean if I tear out a Stephen Gambrel room as inspiration while decorating that I need to send him a royalty check? Are the same people who are pissed at the Seattle couch guy mad as hell at Madeline Weinrib for boosting the prints of Uzbekistan for her own personal gain? Let the riots begin. (Someone lock down ABC Carpet and Home, stat.)


A commenter asked:

Do you think it's all right for Restoration Hardware to rip off this Edouard Bouquet lamp:
HERE

And sell its own virtually identical version as the "Counterpoise Single-Arm Task Table Lamp":
HERE


Is there a line? And where won't you cross it? Or are there no original ideas left in lamps, sofas, pillows, etc. Discuss.