If the course for which a person was originally granted a Student Visa has finished,
then the premise for that visa no longer exists, and it will either expire, or be liable to cancellation.
A person is unlikely to be granted a (further) Student Visa if they are not
(still, or again) a genuine student.
Even if a person enrols in something else, the student will still need to be genuine,
and the department will still need to be convinced of that before granting that person a new student visa.
So, the Pharmacy graduate who enrols in hairdressing just so that they can stay in Australia
is not certain of getting a visa.
And they (mostly) don't need to, if they have applications and/or appeals/reviews on foot.
The purpose of a Bridging Visa is to enable a person to stay in Australia while a decision is made
about their application for another class of visa. This can be days, or years.
A person can be (but is not always and not automatically) granted a Bridging Visa for the duration of an appeal process.
The AAT can make this decision (it's called "making a substitute decision"), but more commonly, will remit the original application
to the department to be remade.
A Bridging Visa does not operate (and cannot be granted) to enable you to stay in Australia
while somebody else (who is not on a, say, a Spouse or Partner Visa linked to yours)
finishes a course for which the other person has been granted a visa in their own right
(even, say, for the few weeks remaining in academic year 2018) .
There is almost always a known date by which a person has to depart. If a person remains in Australia after that date,
then they typically become an unlawful non-citizen, and are at risk of arrest and being placed in Immigration Detention,
prior to being deported.
