Why would you not want to keep accurate records?
Keeping in touch has nothing to do with record keeping. However, you should be prepared to follow up with all your students until it's the student that decides no further contact is warranted. Following up is essential, and important.
A lot of pilots figure that if they get in trouble as an instructor, they're fine with their other certificates, because after all, they're different certificate numbers. Not so.
When the FAA investigates you, the FAA is investigating the airman, not the certificate. Have a problem, you may be facing certificate action period, not merely you, the ground instructor, or you, the flight instuctor.
As a flight instructor, if you elect to provide any flight or ground training, you are required to sign the students logbook. While you may endorse as a ground instructor, don't forget that you are also a flight instructor, and the holder of a flight instructor certificate.
You would be wise to sign the students logbooks for the training given, and to keep accurate records. Failure to keep records is a failure to plan for the unexpected. Keep accurate records. They could be the salvation of your career.