@Sideon "location is not the issue"
Exactly, but the criticism of a "bad" approach is often based on that. People will say "You shouldn't have done it there" when that isn't the issue at all. There is no "good" place for a "bad" approach ; and no "bad" place for a "good" approach.
The "approach" has to be such that the person : has enough knowledge that they are being approached to respond positively if they choose, but not so much that they feel pressured to choose. That means having a gradual lead up, with both parties choosing to "escalate", and that in turn means being able to properly read all the non-verbal communication. Cassanova was apparently successful, because he was good at knowing who would be receptive, like a metal-detectorist knowing where to dig.
At the most extreme, is a wedding proposal. If the person says no, it means you shouldn't have asked.