A member of our province recently asked “What happens if a person with mundane arms joins the SCA? Can they use their mundane arms as SCA arms? And what happens if there’s a conflict with existing Society arms?”
The answer to the first question is found in the Administrative Handbook of the College of Arms, section III.B.7., “Armory Used by the Submitter Outside the Society,” which reads:
No armory will be registered to a submitter if it is identical to an insignia used by the submitter for purposes of identification outside of a Society context. This includes armory, trademarks, and other items registered with mundane authorities that serve to identify an individual or group. This restriction is intended to help preserve a distinction between a submitter’s identity within the Society and the submitter’s identity outside of the Society. Any change that causes a blazonable difference between mundane and Society armory is sufficient to allow registration by Laurel.
So, if you have arms in the mundane world, you must make at least one minor change to them in order to register them in the SCA.
On the other hand, we don’t normally conflict check against all registered armory everywhere in the world, as noted in section III.B.3., “Significant Personal and Corporate Armory from Outside the Society,” which specifies that:
Modern or historical armory belonging to individuals or corporate groups may be considered significant or recognizable enough to protect on a case-by-case basis. Armory is likely to be considered important enough to protect if the owner is associated with important administrative, social, political, or military events and the arms themselves are important or well-known.
So assuming you’re not the Queen of England or something equally prominent, if you kept quiet about it, you could plausibly sneak in your personal arms without anyone catching it. And the College seems loath to retract registrations after the fact, so even if people found out about it afterwards you might get away with it. But I’m not sure if anyone has ever tested this, and I’m not encouraging you to try it. 🙂