Why I have never experienced sleep paralysis?

[Bharmo]

I'm quite new in LDing, but as I have been reading and learning about different aspects of it and I have found a lot of info about SP, there is question that keeps coming back to my mind: Being Sleep Paralisis REM atonia a natural phase in everyone's sleep cycle, why I have never experienced SP or at least REM atonia when, for instance, my alarm clock goes off too early or my wife wakes me up in the middle of the night or I hear a noise outside and had to jump out of bed to check? I know only two people who have experienced it not LDing (and both were scared to death), but why it is something almost only LDers experience? What do you think?