Last year the the local authorities, I think it was the DNR, were walking the docks at Hammond Marina, Indiana. They were looking for the state registration decal. If the boat was documented they didn't care about #'s but said you have to display the decal.
I decided that I should get one for this year. When I went to buy it, they charged me for last year too.

I tried to explain to them that my boat was only in the water for two hours last year because it broke.
They didn't want to hear it.