Okay, time for my two bob's worth on this one...
For starters, I'm more familiar with Victorian laws than NSW, but I thought they were similar. Australian knife laws are NOT the same as the UK - In the UK a pocket knife is illegal to carry if it locks open which is not the case here (again, I'm talking Victoria specifically). Also, there is a 3" blade length limit in the UK which does not apply in Oz.
The basic premise in Australia is that you must have a legitimate reason for carrying one - which includes needing it for work but NOT for self defence. Now, I'd argue that a pocket knife is useful for most jobs, but that's another story - if a cop decided you look dodgy the onus would be on you to prove your legitimate reason - I don't know if "I open my mail with it" would be good enough - there is nothing in the regulations about how you must use the knife at work for it to be acceptable.
Sadly, the best advice is "don't carry anything that looks mean!" (so the 3" length rule is worth sticking to, even though there is no mention of length in the regulations) - and don't be caught in the wrong place at the wrong time! :sick2:
When I was living in the UK, I nearly had my UK Model Spyderco (which is a lovely thing and entirely LEGAL in the UK) confiscated when boarding the Eurostar because it looks mean - I wish Spyderco had printed "UK Model" on it - that would have saved some stress! I was also carrying a 2 bladed "gentlemans" knife which didn't concern them in the least and neither did my Leatherman Charge (with two 3" locking blades and therefore technically illegal). Similarly, I visited many museums etc where security was tight - my Swiss Army knife never raised an eyebrow (it was usually surrendered to security and returned when leaving the building). Perception is a big thing!
Assisted openers - for sale over the counter and not specifically mentioned (in the Victorian regulations at least) so they're legal - but they look mean when you open them so be careful where you use them.
Flick knives, which are banned everywhere and considered the spawn of Satan are, in all honesty, only banned because the bad guys use them in movies! They are no more dangerous or sinister than any other knife - but it's the perception. In the 18th century, an attempt was made on the life of the king of France. A ban on flick knives followed where the penalty for having one was execution! Of course, the knife used in the assassination attempt was NOT a flick knife!
There is a LOT of misinformation around about knife laws - people get rather carried away with things. I wish I had a dollar for everytime I've been told "new laws have come in banning knives" - what bullshit! However it does pay to do a little research and be sure of the details. I'd be amazed if there was a problem with Spyderco knives in NSW (unless they've gone with the ridiculous "must not lock open" strategy which defies logic :thinking
- however, some Spydercos DO look anti-social, and those are best avoided if you're concerned about problems with the law.
Hope that's some help!