Would be relatively easy I would have thought as the FIA's own rules specify when it should happen. There is the part about any car but that follows on from a statement saying the message goes to ALL teams. It also specifies it is a requirement and that it must be the LAST lapped car that passes the safety car. The last lapped car had not done that. There really is no legal case to be made to defend it, the rules clearly give no situation in which the SC could have been brought in when it was and it should have finished under SC.