Ownership of paintball guns is regulated under the state-level firearms act in most (all?) states and territories.

You can use them under the direct supervision of the licensed owner, but it's still quite restrictive. If you were to take one and shoot at cameras on the street it would vandalism plus firearms offences, most of which start at inversion of innocence, massive fines and move pretty quickly into prison time.

If you actually purchased one yourself in Queensland, you would need a Cat A firearms license, genuine reason, permit to acquire, safe storage etc as for a firearm.

NSW used to be similar, but a few years ago the state government had a rare moment of common sense and did away with most of that pointless bullshit.