That is far from the reality in a real storm. During the Perfect Storm the boat I worked on at the time was at the most protected dock in Little Harbor, NH.
She was 55 feet and when the break water at the mouth of the harbor went under water they had four to five foot breakers coming in on top of high winds. I was at sea at the time on a delivery and could not help and had my own set of problems.
Sadly the boat was snapping 3/4" dock lines like guitar strings. The minute the dock line came in contact with anything, gunwhale, dock etc. it would snap like a shot gun. There were four guys there for nearly 20 hours replacing dock lines, fenders and running the engines to lighten loads yet the boat still sustained well over 100k in damage. The owner dropped off a spool of 3/4" three strand and they went through the entire spool in 20 hours even end over ending some lines. Low tide offerd some respite from the breakers but the winds still howled
The photos below are the result of a Nor'Easter at a dock. These boats were secured as best as could be but still bit the docks and sank.
A few days after the storm:
My boat survived that storm, on her mooring, without even so much as a scratch.
Here's a video of that storm. All the boats on moorings in this cove survived too.
I'll take a mooring over a dock any day of the week in a real storm..
YouTube - Why Not To Cut Corners On Your Mooring