Perth / Western Australia

Yes, but you have to weigh the benefit against the costs. Seatbelts are a no brainer because there's literally no downside to mandating them.

Helmet laws have already proven problematic because of how they have proven to reduce how many people cycle, which reduces people's life expectancies...by more than the traumatic injury caused by a crash without a helmet would. Things that make cycling more difficult for people, even by a tiny amount, are detrimental to public health and should be seriously scrutinised.

Chain and sprocket guards...what would be the benefit of them? The WA government has already reversed their rule about schools requiring them after it turned out they never intended it to have as big of an impact as it did. And to be frank, the safety benefit of them seems likely to be quite small. Maybe for children it could be worth it, but I have never heard of an adult receiving an injury that would have been prevented by a chain and sprocket guard. Meanwhile, it would make doing routine maintenance of your bike a much bigger hassle than it currently is, and maintenance is required to keep a bike in good working order.

It's such a non-factor that chain and sprocket guards basically don't exist for road bikes. There are a couple of extremely niche products out there that do it, but they're not exactly a standard off-the-shelf product you'd find at your local 99 Bikes. That should be a pretty strong indicator that mandating them is not really the way to go.