It's probably one of these high rise jobs.  Arond here the apartment
market
is so tight and so expensive that the cat owner may not have any
choice.

I would be thankful that the apartment allows cats, then keep the cat
indoors.
I don't know if the cat would survive a fall, I'm don't I think I want
to find
out with my cat.

As far as how to keep the cat from going over the edge if it sees a
bird
or something else, I'm not sure you could short of fully enclosing the
porch.

waaal....moving to a place with a balcony cuz it's a great way to have an
apartment: an outdoor space without having to go outdoors, view etc.. Cat
loves it and hate to deny her the stimulus and space but gotta find the
right way to catproof it so she doesn't have an accident. Not worried about
her jumping, but getting fixated on a bird or something and just forgetting
herself and stepping off into nothing. Failing that I guess I could keep her
off it but that doesn't seem right, plus she'll never stop nagging me.

Only if something makes it forget it is on the balcony.  Build him an
outside enclosure.  MLB