Actually another way of looking at the IP# on Broadband is that its equivalent to a Telephone # or Cellphone #. If the person at the other end of the connection knows how to use system logs then they have the Equivalent of "Caller ID" on their computer. If you limit the # of connections but have a list of allowed callers then you have something like "Call Waiting" in place.
Seems things don't Really change all that much.
