THey have barely any root system at all. When I lived in TX, my neighbor planted a pair of them in front of his house that were over 20 feet tall. They had to be held in place with a pyramid of 2 x 4s for about 5 years. (The whole neighborhood just about stopped talking to this neighbor because they looked so ugly.) Then one day, a truck pulled up and yanked them out. They were nearly 30 feet tall by then. My neighbor sai that he'd sold them. But I lived in fear the whole time that they were there every time hurrican season came around. I was sure that one of them would be driven right through my living room window. LOL
They usually hold up better in hurricanes than trees with big woody roots. Fibrous palm roots are kind of stretchy, and are not prone to rotting when soaked.
Their root ball is bigger than what the nurserymen take. They leave a lot in the ground. To transplant them [or any tree] it’s best to come and cut a circle around the tree the size of the container or basket then leave it in the ground a few months before pulling it out; it will grow shorter bushier roots. That helps prevent the shock it would go through if all its roots were cut back at once.
Of course they don’t shock as bad as other trees because a palm has live wood all the way through full of water, starch/sugars, etc... it gets them through rough times like a camel’s hump... whereas other trees have only a layer of live sapwood.