In order to promote groups which are either under-represented, or under-achieving, organisations will engage in positive discrimination. There are 3 groups in today's society which are afforded such treatment. The first is Women, the second Youth, and the third the Old. We have thus both Age and Gender discrimination. There is also the possibility of providing extra benefits. By pampering these various groups, the hope is normally both to encourage and develop existing players, and to gain new players.
Anonymous: There is no such thing as purely ' positive discrimination '. Any discrimination designed to benefit a group at the expense of other groups is logically also a negative discrimination against the groups discriminated against.
Pair Go normally refers to a perfectly gender balanced tournament format, where teams of 2 players (thus composed of 1 male and 1 female) play against each other. This is believed to provide a non-intimidatory atmosphere for female players.
Closed tournaments allow the participants to win titles, wheras, in Open tournaments, they might struggle to find success. Closed tournaments can also provide an atmosphere that could be seen as more appealing for the participants. Many countries have Women's or Veteran's championships.
A workshop provides a non competitive environment where learning can take place. By closing the workshop to other groups you can aim to eliminate the possibility of intimidation or denigration. Thus the participants should find themselves in an environment more conducive to learning.
See also Discrimination In Go