RemotingServices.Disconnect is probably one of the confusing APIs in remoting. It doesnt correspond to RemotingServices.Connect, but rather to RemotingServices.Marshal. Disconnect is a server side API to disconnect objects which are currently published via remoting. You might have noticed an exception if Disconnect is called on a remoting proxy instead.
This API is can be used to basically "unregister" an object. Note, that any current active invokations on the object would still succeed.
ps. It feels good to be blogging again after more than a month.