I use barrel swivels to lengthen the distance the hook hangs back but as far as it locking up and the fish getting leverage I don't buy it. The plug is not attached to anything solid but rather mono to a chain swivel and in the absence of the swivel the line would just twist and offer no leverage. Also, if the fish has both trebles in the mouth it would defeat the purpose anyway and I can't imagine arguing that one is better than two.
States may differ in rules, so always check the fishing rules in the state you plan on fishing.
You can run 3 trebles if it is Oregon
I use barrel swivels to lengthen the distance the hook hangs back but as far as it locking up and the fish getting leverage I don't buy it. The plug is not attached to anything solid but rather mono to a chain swivel and in the absence of the swivel the line would just twist and offer no leverage. Also, if the fish has both trebles in the mouth it would defeat the purpose anyway and I can't imagine arguing that one is better than two.