yeah snaring is illegal as hell in most parts of aus, to the best of my knowledge.
Old timers round my area (southern qld) used to swear by looking for where hare would run under the bottom strand of a fence, then set a higher than average rabbit snare in their path. Then again, most of them seem to live off corned silverside and lamb chops so it's either not a very tasty, or a very convenient option.
Legality aside, apart from small animals that may hit a snare hard enough to choke quickly, or break their own necks, a well set snare can mess up any critter from a hare up to a bull. A lot of the more feral stock and native animals in my area show significant injury at times from being tangled in old discarded wire, let alone snares. We had an 800kg or so cow kill herself in our bottom fence a few months ago. Knocked off the top strand, panicked, bolted, she ended up with both frong legs cut to the bone and a metre or so tight around her neck. We weren't home at the time, but from the damage to the scrub around her it was not a particularly quick or easy way to die. And that's nearly a ton of animal, probably running full til against heavy gauge plain wire.
Even if you go the "funnel' approach, or under a fence, or whatever... you can still easily trap bandicoot, quoll, juvenile padymelon, large monitors etc. It's kind of a ****ty thing to do.
Fun to practice, like I was told set the bottom of your noose one fist high for rabbit, one fist and a thumb high for hare... it's nice to know. But just doing it all over the place is a bloody good way to just injure or torture a lot of animal life.