My buddies and I have been doing the structure on a string concept for years. We fish a very shallow lake with little structure or winter weed growth. In mid January the number of fish under the permanent always seemed to decrease. The crappies would dissappear, and the only chance at a walleye would be in the middle of the night. After we started dropping these little “structures”, the bite, especially during the daytime, always picked up. We have always kept it low key because it seemed like a grey area in the regs to me.
A few years ago I remember reading in the regulations that a person could get a permit from the DNR to make structure. It said something about not creating a hazard for boats even in low water conditions. I have never tried to get a permit, but my buddy claims that they have gotten them before.
Be careful about putting them too close to the house as others have stated in other posts. I have had Northerns tangle up every struture in a matter of minutes. What a mess.