When I do these jobs I make sure that the ladder is about 4 ft higher than the balcony rail, and resting on the wall, it's all about the way you transfer your weight from the ladder to whatever your going to stand on. In my case it's usually a convenient chair. If no chair is available I take a small set of steps up with me first.
When you step over, you place your leg on the inside of the rail, this holds the ladder in place.
If your careful, and I am, there is no more danger than stepping onto a flat roof, in fact less as that first step off a flat roof onto the ladder is something you have to be very careful with.
I wouldn't like to wash the underpants of some on here, if the were doing the job 50 years ago.