Signing off is very much like signing a virtual scorecard. You are agreeing that the data from your round is accurate and is what happened out on the course. We have social features in the system such as Leaderboards, this allows one Shot Scope user to compete against another user, this system breaks down if users are signing off false data. If you do opt into any of our social features please make sure to sign off accurate data only.
It is good practice to only sign off a round after the data is accurate to ensure that your statistics are correct. Signing off inaccurate data will mean you are analysing incorrect data which is counter productive.