Hi blackriderx,
That would depend entirely on who you ask. For those that would prefer no fire barrier in their mattress (usually to remove the possibility of having chemicals in their mattress) they would say yes and for those that are more concerned with the possibility of their mattress contributing to the risks of a fire they would say no. It depends on which of the risks (chemicals or fire) would be a bigger concern to each person. There is more in post #4 here about fire barriers as well.
Phoenix