We are taking the position that if people don't know about something inside of us, they can't use it to hurt us. The problem with walls is that whatever is behind the wall is a secret. Yet we form or join support or discussion groups such as this one because we need to take these issues out into the open and talk about them. But when walls are our only protection, it's hard to tear them down and leave ourselves exposed. It's especially hard when those secrets are painful ones.
Boundaries are an alternative.
You can talk openly about yourself across a boundary, and know that you are safe. Boundaries are limits on what we will do to and for other people. The best boundaries match the limits of our control. We cannot control what others do, so we can set a boundary that limits us to not attempting to control others. Setting boundaries gives us back control over our own lives.