Right now if a domain socket exists it is unlinked before being recreated with a server.listen. With modules like hook.io, dnode, or ones that create servers and clients for mesh networks this is a problem. Creating a server prior to trying to connect is the general way to test and create at the same time for a mesh network, this behavior means a connect and create on failure test is used. Connect and create leads to race conditions. Also, the unlinking is not consistent with other socket behavior and the man pages for binding unix domain sockets.
This is how it works in Node 0.8.