URL use after a server move

We moved several repositories to a different lab about a year ago.  We needed to change the IP address, but were not able to change the DNS record, as there were multiple repositories on the server we moved from, and users needed to be able to continue using that hostname.  So for users of the repositories that moved, we instructed them to update their local hosts file to send them to the correct location and to ensure that links between records continue to work properly.  What we are seeing is that users are simply choosing to use the new IP or the DNS name registered for the new servers instead of the old name, with a hosts file entry.  I had been under the impression that this was a bad thing for them to do, but I have not seen any complaints from users doing this.  Can anyone tell me if this is causing some massive problem like links between records are now being created with the IP instead of the original hostname?