There are cases where the user does not want to receive the legality warnings for crewmembers (i.e. contract pilots) that are not maintained in the FOS database. There may be other examples (i.e. other positions) they desire to silence warnings for as well. One solution is to turn off the legality warnings for any select crewmember.
This option can be found in the PERSONNEL DATA / EMP tab. Checking the box for 'Exclude from Legality' will prevent the user from receiving unwanted legality warnings.