When entering a new phone number or email address, check against all inactive/active numbers and produce a warning message so that the phone doesn't get added again.
Also standardize the data entry so that the user can add only the number and allow RE to add dashes, etc because when we export data, those numbers do not come out the same and we have to clean all the numbers before we can match against them to identify duplicates.
Anonymous again...
How can RE warn when the data is not 'saved' in a record. Sorry no votes from me on this one.
Also, in configuration, you can set format for phone #s. We just enter the digits. The "( )" "-" are all auto entered.
If by any chance you come back to read the comments on your post, consider asking if something is possible on the user forums. RE can do more than most people realize.