They should have shown her big fat boyfriend come out there also, so that #1, I'll feel safe about the weight rating, and #2, I'll know that even if I'm big and fat, this window will help me land babes.
If you'd fit such a balcony to an existing app building and the balcony indeed would hold the weight of a group of people, I would still wonder whether thehouse's frame would hold the balcony.