Even though I'm the resident newbie here, I have to disagree with you, 4seasons. I think what people with social phobia need is a lot of support, and what they don't need is people dismissing their illness, merely telling them to "tough it out". Personally, I have no trouble leaving the house, going shopping, eating at restaurants, and even, believe it or not, public speaking. However, what is very mild in some circumstances can become extremely severe in others. Simply put, work is where my social phobia manfests itself the strongest. A lot of people think I'm a faker, but those people haven't seen me at work. There are a lot of other situations that bring out my social phobia, but work is the one I can't get a handle on. When I can't handle the social pressures of work, depression, mood instability, and even mild psychosis rear their ugly heads.
Recently, I knew I was headed for a meltdown and I couldn't get anyone to take me seriously. I lost my job, and all the people who thought I was faking or not being tough enough contributed to me to becoming very depressed. Even though I never attempted suicide or honestly thought I would do it (although I was indulging such thoughts like a sick fantasy), I said I was going to commit suicide because it was the only way I could get the attention I had previously, but unsuccessfully, sought for. I was admitted to the hospital and, even though I normally hate hospitals, relished the time to recuperate.
You may think I was being dishonest, but I know I was reaching (or had already reached) my breaking point. And even if I wasn't suicidal, I needed help urgently, and I did what I had to do. So yeah, I get income assistance from the government now, and this will probably be the case for the next few months. I can't help but think I would be one of those people you would accuse of abusing the system; I seem to fit your criteria afterall. But the truth is, everyday people and medical professionals alike are a lot more inclined to dismiss or shrug off someone with social anxiety than depression, so I felt I had no choice. Bear in mind, however, that I was severely depressed because of the perceived hopelessness of my situtation and was least somewhat suicidal (depending on how you define it). All I know is that I'm getting the help I need...with any luck all become a happy, productive, tax-paying member of society some day. I can pay the government back 100x.
Put briefly, I don't know what your story is or if you suffer from social anxiety yourself, but the point is, you never know what's going on inside someone else's head. Your sister may be dealing with unique issues that you have never experienced or don't understand--although it is worth reminding you that this sort of thing is often genetic and runs in families, so if you have it, chances are someone else in your family does, too. And like I said, when a person with social phobia or any other mental illness works up the courage to ask for help, the last thing they need is someone to accuse them of being a faker or a weakling. Quite frankly, admitting that I have social phobia is rather humiliating, and not working to support my self and family is humiliating, so I'm going to assume that people are less inclined to lie about this sort of thing than you may think.