Disclaimer, and thoughts:
1) The views and opinions expressed in this article are not necessarily my own;
2) I do not smile at those who are sexually harassing or in other ways threateningly approaching me. HOWEVER, as I read this article I asked myself, "What do I do? In what situations am I unwillingly approached?"
A: My default is to stonewall and ignore the person ogling me. If, despite or as a reaction to this, their behavior escalates, I then attempt to leave the situation somehow. I am luckier than the author in this because some of the situations she describes are ones she can't leave - waiting for the bus, riding public transport, etc. I don't know what I would do then.
B. The exception is that if I'm on foot and someone is catcalling me from a vehicle. Then my default is to flip them off. This has backfired on me exactly once, but that backfire did result in a nasty fight between the driver of the car and my boyfriend at the time. It seems the risk of a nasty reaction is low but when it happens, boy, it's gonna be a doozy probs.
C. I've had way less of these encounters turn to threats/violence than the author has. I'm guessing she lives in a more city-like environment.
3) This issue seems very clearly related to both
a) POC and hair touching
b) Tattooed/body modded people and skin/mod touching