Solidarity refers to how you act together in the face of oppression to strengthen and build your movement.
Some jail solidarity strategies and court solidarity strategies involve using the strength of numbers to pressure the system into assuring equal treatment for all, and into accepting demands that they reduce or drop charges. Activists have employed a variety of tactics to ensure that the police keep them in jail, where they cost the system the most money and trouble. Activists arrested in certain actions have also all pleaded not guilty so as to clog the court system.
These strategies require planning, preparation, and the commitment that arises from the group's decision making process. They work well in situations where there is some social restraint on police brutality, and when people's differing needs and life circumstances are respected.
Guilt free solidarity can empower the people who take part in it: but it is also exercised at a cost. Even in the US and Canada, political prisoners have been brutalised, tortured and even killed. Regular prisoners face these dangers every day.
In countries and situations where there is less restraint on the police, where people are being severely beaten, brutalised, or potentially murdered in jail, solidarity may best be exercised by putting pressure on the system from outside.