killer fan palms
The Mexican fan palms lose their fronds more easily, which makes them cheaper to maintain but consequently more dangerous for anyone below them. The California fan palms are the thicker ones that tend to keep their dead fronds hanging almost to the ground, but the drawback is that critters, such as rats and snakes, like to live in there. (We use rat poison stations in our yard to keep their population down, so our tree trimmers haven't had the usual hordes of vermin come pouring out when they visit--an amazing sight to see if you ever get a chance. One guy, however, did let out a scream once, his chain saw having hit a live one. What a mess--blood everywhere.)
Apparently, these palms have been planted in parts of Hawaii, where they're becoming rather invasive. It's not surprising considering how they drop an endless supply of small, hard dates that quickly mushroom into more trees. Lots of lawns in Riverside are actually full of tiny palms trees that just keep getting mown with the grass. They're easier to spot in the borders where they quickly become real trees.
If you have fan palms, you'll need to have them trimmed regularly due to the fire hazard, to keep the critters at bay, and also to reduce the chance of death by palm frond for you and your neighbors. Pick up fronds that drop (once the winds die down) and get them out of the street to prevent punctured tires and to keep your pets and children from getting hurt. Walk around them, don't step on them, as the spikes can go through shoes, and remember to drive around them.
Recently, the City of Los Angeles has been trying to decide what to plant now that the older Mexican fan palms throughout the city are nearing their life expectancy. They're now looking for trees that will actually provide some shade during the summer (thus reducing cooling bills for a lot of residents!). But there's no mention of the trees' hazards.
LA Times article
California versus Mexican fan palm
Report on Fan Palms as Pest in Hawaii

