Let us examine a fictional chat log from a server that has no brick public domain.
Wedge enters the server at 1AM EST. No one else is on. Wedge proceeds to place baseplates all over the bedroom floor. He then leaves. Later that day, a few people decide to build. But no, what is this? They don't have permission to build on the players bricks! And the server host is nowhere to be seen...
Bad things happen without public domain...
If you don't like public domain, I believe Badspot posted how to increase the public domain length.