Well it looks to me like most of the places they're walking on were meant to be walked on or at least accessed for maintenance. So do it at your own risk if you wish, but please don't do any cartwheels.

By the way, there's nothing keeping anyone from dropping a full can of beer off of a balcony or falling off their balcony after having too much beer, so there's all kinds of risks with highrises. I've been up on enough of them outside to know how windy it can be, and I really gotta wonder how patio furniture doesn't just blow off. I'd seriously consider tying stuff down.