Recently I posed a definition of coercion as the existence of a difference in power. In that post I said the following thing: "we need to exert constant effort to avoid coercing others." I've just realized that, as stated, that sounds a little incoherent. Here's an attempt to clear that up.
On my definition, coercion is impossible to avoid. If you have more power than the person you're interacting with, you are by definition coercing them (at the very least, to make nice and be friendly to you). How, then, even with "constant effort" can we avoid coercion? Well, this is one way: work to reduce your own power over others. In other words, making a commitment to non-coercion means making a commitment to non-power.
This entails a certain sort of pacifism, since obviously acting violently is only possible through power. However, I don't think that my definition and its associated principles strongly condemn 'punching up the power differential': violence against those clearly more powerful than you.
There's an interesting related question: if you're interacting with somebody more powerful than you, do you have an obligation to increase your power accordingly?