Perhaps to control which records a tech can see when logging in/out?
What are you referring to when you speak of "forward and back arrows"? Are these records listed in a portal and you are referring to the scroll bar?
If a portal is not being used, you can control which records are reached, by restricting the found set of records to just those you want to allow the user to see. Then simply stepping/scrolling through the records will not bring them up though a find or show all records could.
It's possible to set up record level access so that only certain records may be viewed or edited by a given user. If that's what you want, see Editing record access privileges in FileMaker help and scroll down to the section titled: Entering a formula for limiting access on a record-by-record basis.