My own opinion on undercover officers: Dont.
From OOS perspective ; there is a lot sec vs antag dynamics that change whenever the receiving end of antag is either a random crewman or an officer.
Its very underhanded considering a normal crewmember *cannot* interfere with an antagonist much, and surely, cannot end their round by an arrest. they are only permitted to defend themselves and do their best to disengage. This makes antagonists know what to expect when acting (and imo that's a good thing, antagging should be harder than it already is). if you add paranoia of "what if there is an undercover sec here", or even confusion whenever that crazy baldie is trying to valid you. it makes it much harder for antags to act - meaning more boring rounds for everyone. (because sec effectively removed all antags early due to tricks)
Not to mention, Antagonists fighting officers will behave differently; as they are permitted to kill pursuing officers, while killing normal crewmen is not desirable.
One could even argue how its not "playing your job responsibly" and "valid hunting" but I'm aware most people will find that a stretch.
It even makes a lot of sense from IC perspective. Officers are people of the law, and considering they have a very special position within the law (permitted to use weapons, assault on officers has a different charge, allowed to enter restricted areas during emergencies), any would-be officer must be easily identified and probably in uniform.
Of course, I don't want to take away people's drips, I don't use stock uniforms either, but I still think the outfit should easily identify you as an officer, and not try to gimmick you into looking like a completely different role. and I agree that it should extend to command roles, as they also hold special place in law and special authority on station. They should be easily identifiable as their position and not roleplaying as a different job entirely. I remember having a round with a HoP who insisted on wearing a skinsuit and there was nothing in law or SoP to enforce proper dress code. I would very much welcome some slight moderation from SoP.
Even a simple "should wear easily identifiable attire or uniform of his position" would go a long way - since it would be SOP, it is not law and therefore can be ignored for emergencies or other edge cases(or just ignored so people can wear their drip), and gives the heads and IA departments some hook to help maintain proper dress code among command and officers when these people dress ridiculously.