Which of the following would not apply in the registrar's opinion to decline the issuing of a security license to an applicant?

The issuance of a security license typically involves meeting various qualifications that ensure the applicant is fit to hold such a position. In this context, a high school diploma is generally not a mandatory requirement for obtaining a security license. This distinction is crucial because many regulatory bodies have criteria that focus more on the applicant's integrity, past conduct, and any declarations made during the application process rather than strictly on educational qualifications.

The other factors mentioned—making a false statement on the application, having a history of misconduct, and existing grounds for refusal as prescribed by laws or regulations—are all significant concerns that could rightfully lead to the denial of a security license. These aspects directly relate to the applicant's reliability, honesty, and overall suitability for a position that often requires a high level of trust and responsibility. Hence, the absence of a high school diploma does not hold the same weight in assessing an applicant’s qualifications for a security license as the other options listed.