In a sense, yes. By using the IP filter on the RU Server you narrow the list of remote IP addresses with which the server is allowed to communicate. But then again, the IP address of the Viewer or Host may be changing - for example, when the Viewer is installed on a laptop and the laptop travels with its owner often.
So it is only recommended to use the filter if you are sure that Viewers and Hosts fall into a certain IP range and will stay in that range.