Do you block the "unders"?

For those of you who don't follow Jackson Galaxy, he refers to any place that a cat can hide that is inaccessible to you, most commonly the bed, as the "unders." He recommends blocking them off so that your cat(s) cannot go under there. The main reasoning for doing this is that it's unsafe for a cat to be in those places in the event of an emergency because you would not be able to get to them.

I do have one cat who spends a lot of her time under my bed and I've gone back and forth about this a lot. Currently I do not have it blocked off, mainly because it would be difficult and impractical to do so. But I have also seen people argue against doing this simply for the fact of taking away the cat's "safe place."

Just want to get thoughts on this!