I've driven them, frequently on the docks and also operated Bobcats, all kinds of equipment. Never needed a license.
Not that the docks I worked at were so concerned about legality. Some people have the knack for running machinery. It's not bad work... til there's an accident. I've dumped a heavy palette on a bumpy incline and once drove it through a wall (again there was a steep incline and I'd been working over 30 hours straight.) Shit happens sometimes.
If all your surfaces are level and the palettes are properly stacked and balanced you'll rarely have an accident. I was operating up and down hills and over bumpy docks and into tiny buildings and crazy terrain like that. I used to see my boss falling asleep as he was operating the thing. Guy was a stoner. Plus we were all seriously overworked there. Seafood processing. That's some hard and dangerous work. They'd even having driving the big semis up and down the coast with no license for that either.
Unloading the boats from the dock winch was probably the most dangerous part of that job. You standing on the edge of a dock with a fishing vessel parked at a lower floating dock. At low tide that can be quite a drop. The eddge of the dock is all oily and wet and so are you, and you're winching up 200 lb totes of fish stacked in three.... and half the totes are broken and shit, so like it would be really easy to take a fall. Then there was constant dock repair, ice house machine maintence, fueling vessels and trucks, dealing with flash freezers, and setting up all the chemical and packaging for the processing, managing the processing... fkn crazy hard job. Accidents were not uncommon, and everyone was baked. We smoked weed constantly at that place. Then I got into fishing.... which involves even more weed.