I've launched my Mavic from my 300ft balcony. Although 'not safe', it's really not that hard if you're somewhat competent and you stay calm. And you definitely get badass footage... Here's what to do:
1) Keep it far enough from your balcony railing that there is no magnetic interference (place it on a table if possible).
2) Launch it from and back to the balcony flying backward so the front sensors don't pick up the railings.
3) Don't use the 'Return to Home' feature as it will try to land on the roof of your building... fly it manually.
Check out my balcony launch capturing the Toronto skyline: