So this woman approached you and became loud and demanded money? Was she a shopkeeper or something? That's the kind of situation where if you don't see security handy and they get a little pushy you pull out the mace It sounds like you were borderline mugged....

No, she was a general customer/lurker of the shopping centre. Luckily I don't carry much money on me anyway. So if she did steal my handbag it would not have been worth it for her.

There are often people begging in shopping centres and bus depots - they tell the kind looking people that they have lost their wallet, or just ask if they could give them a dollar towards their bus fare...
Some of these people are genuine, and every once in a while I will help someone (give them the benefit of the doubt).
But if they threaten me, or act in an odd way I would not, and if possible I would raise my voice enough for another person to hear me, and say something like "No, I am not going to give you my money".
Clearly this woman followed you to a place with nobody else around, and has done this sort of thing before.
Giving her some money, looking at her carefully so yo can give the police a description, and going home unharmed is the best option - but it isn't nice!

They are all over the university busport(who knows why, students don't have any money haha). I usually give them $1 or $2 if I have it but usually I am lucky to have 50cents on me, since there is eftpos everywhere now and I have an automatic re-loadable bus card I do not see the need to carry money.

We have the same here, although the same people can usually get the same amount by simply panhandling for it. I've not heard of anyone pretending to be asking for money cornering people and demanding they give them cash. If this is something that happens often, as you say ILF, you may want to start carrying pepper spray. Seriously.

No this doesn't happen often. Though there are heaps of people generally begging at the busstop, who are not threatening or whatever.

I just read up on pepper spray. It is legal to carry it in Western Australia but not some of the other states. Someone was jailed last year for it in NSW I believe.

Well it's good that it is legal! You basically just aim for the eyes and it incapacitates them for a minute or two, long enough for you to make good your escape. Or you could carry an air horn. That'd definitely freak them out

Panhandlers usually tend to not be so pushy. At least not those I have encountered. But I have heard of instances like yours. Usually they tend to be all bluff, and telling them to back off works. But with an individual actually threatening it's best to be safe. if you do not have pepper spray, or are not permitted to carry it by law, it would be prudent to have remained in the restroom, and called the police. If you have no cell phone make as much racket as you can to attract attention of others.
If the person becomes physically aggressive I can only suggest a good self defence. such as a good heavy purse with something hard in it.

I like having my uni textbooks on me, those things could knock someone out. This women was actually small, so it wouldn't have been too bad if she became aggressive, since it would have been two of us against her. She was an Aboriginal women, and some of them tend to play the "racism" card as soon as you don't give them money. Though I shouldn't have to give anyone money, I am a student for goodness sake.