Maybe this way no one steals the lines. Seriously, I bought my prior O'Day at Milford Boat Works and thought they were a pretty class act; I don't remember anything unusual about the docks, but its about 8 years since I was there. Were there pilings you were expected to use?
Yes some pilings, but most boats even very large boats were tied up to the rings.
Must work as it looks like it has been that way for a long time. Just defies logic as to how it could possibly work.