well, I don't think its that common for people to ignore these - look at how many people fled the tampa bay region. and the barrier islands like Sanibel had almost 100%evacuations. but unfortunately, I think alot of the people that we now know were in the eye, thought it would be mostly a flooding event for them, as opposed to a direct hit from a cat 4.
Speaking from experience of living in Homestead Fl and having lived at the Virginia/NC border for years - one big reason why people do not leave, including me a few times (no, I'm not in a mobile home) is that you bug out time after time after time, and the hurricane doesn't even get close.
When Floyd was threatening my area a few years back, the Keys evacuated as well as mandatory evacuations for trailors/mobile homes in Homestead. People left, Floyd didn't even get close to us. The next time there was an evacuation for trailors, not as many people left. You become complacent, thinking it's not going to hit you. Even living in an area that has been destroyed by a storm.