Correct, marinas are tough spots because you could have the worlds best electrician wire up the place, everything properly installed GFCI to all the dock supply and then a guy could be running a generator and back feed. or someone keeps tripping the breaker and the property owner calls out the mechanic from the dock who replaces the breaker with non GFCI. Its a tough environment and people who shouldn't touch it often do.
At your personal dock a few things that can really help, make sure to test the outlets buy a GFCI outlet tester and check them periodically. You can have layered protection and should avoid having more current available than needed, Does the dock have a hot tub and need 100 amps or is it just the lifts which need 20 and the receptacles which only need 15, size it appropriately have GFCI breakers even though they cost more instead of GFCI daisy chained receptacles.
Make sure any extension cords or items that are plugged in are secure and away from the water, strap them physically so they cannot fall in teh water and have in use boxes covering the powered item. Many shocks are from wet people handling the power cords.
Consider having an electrician install switches to power off the outlets, no need to have the whole dock powered all day every day you could switch the lifts and the dock receptacles from shore so that they can all be shut off.
Lighting can be low voltage LEDs on DC instead of AC line voltage.