The past three times we've been to Long Street at night
1. Attempted theft of my wife's cellphone, beat the crap out of the guy until he threatened to call the police, idjit.
2. Successful theft of friends wife's handbag at some Mexican place (incl iPhone)
3. Some street ****er swiped my r30 ebay watch... I remember him doing sone weird, trying to be overly friendly, and sell me something handshake, 5min later I noticed my watch was gone. (The reason I use cheap crap when we go out, either stolen, or fights (more northern suburbs)
the thing is, there is loads of human traffic in the CBD as everyone flocks here, these things you mention are for all intents and purposes petty crimes if you consider how dense the City is. I walk around in the city any night with no issues- especially after I realise at 11pm I haven't eaten and there is nothing in my flat to eat. I am a trustee in my building so I engage quite often with other residents and the issue of crime and safety has never really come up, in fact everyone enjoys staying here.
I used to live in the suburbs myself and compared to the suburbs I think its a much safer area than most areas, although the statistics won't back me up on that.