No Gravity For You: Subverted, since the knowledge of how to move in microgravity is commonplace, and microgravity-friendly martial arts are almost as commonplace. And, indeed, a majority of spacer habitats and starships run without gravity anyway. Not like they’re a bunch of dirthuggers, y’know?
(And if you are using spin gravity, stopping the spin – which turns off gravity for the whole habitat – is very definitely not something you do this casually.)
If you are using vector-control gravity, however, the attack mode you use isn’t disabling the gravity, it’s reversing the gravity repeatedly and quickly (a maneuver delightfully referred to as “grav pong”) until you’ve bounced the villains into submission. Or unconsciousness.