It seems that everyone is correct in their answers. People used to drag chains on the tailwaters of our major reserviors (Bull Shoals, Norfork, Little Red). It was common practice to use chains to keep the boat trimmed up while drifting in the currents. After seeing the problems caused by draggin' chains in the sensitive microenvironments of these tailwaters, Bull Shoals banned the usage. It is still legal in the other tailwaters, but it is highly unethical.

The use of a chain in a lake is completely different. There are no restrictions on any lakes or rivers other than those mentioned above. Your not going to tear up the bottom and your not going to destroy grass, brushpiles, etc. I'm pretty sure the chain technique was developed in the old oxbows off the Mississippi River. These lakes are relatively shallow, mud bottom lakes with little depth change. This is the proper application of using the chain.

If you are fishing a lake, such as Ouachita with deep major depth changes, a chain is probably not the best method of drifting. A driftsock will work much better in these applications. But if you are fishing stump infested shallow lakes with little depth change (such as Conway), a chain cannot be beat.