We print for a large skate brand, and they rip off something new each PO. I asked him about the legality and the cease and desist letters he must receive and he said he can wallpaper his warehouse with them. For every letter he receives he writes them back with the PO #'s, and reveals how many they actually produce and not once in 25 odd years has anyone ever taken any further action against them. Qty's are in the 500-2000 piece range. I think in most cases it will cost a corp more to legally strong arm someone than its actually worth, in these cases. If it were 100,000 pieces they may be getting a different letter...
He said "This industry was built on parody branding in the 90's" and its quite true as illustrated with Jason Lee!