A neat idea would be a new military-schedule order, in which one can assign individuals (or numbers) of dwarves from a squad to specific nobles, general nobility, nobility types, specific dwarves, of visitors (who are neither leaving, just arriving, or presently at a tavern).
Maybe with the update that includes arrests, we can define different levels of strictness and responses to acts for these on-duty dwarves as well.
Strictness levels:
-Stalk. Least strict category. Makes no effort to protect their target. Instead, merely does it's normal military duties while following them. This can entail fighting enemies of the state, on the way, but only because the dwarf's a soldier on the job.
-Stop only assassins. Will stop invaders, wild animals, assassins, or anyone going at the noble with lethal or worse. Drunken brawls and roughhousing mostly ignored unless the noble is very seriously wounded)
-Stop attacks. Intervenes with all of the above, but will also cut in to brawls that the noble hasn't practically won already, and roughhousing.
-Enforced manners. Highest strictness. All of the above, but guards will also intervene against those who attempt to socially fight the noble (accusations, epithets, arguments, etc). Spitting on the noble, shouting at the noble (depending on whether the noble has a trained consoler skill or not), and damaging the noble's property are all off limits.
Enforcement levels, on the other hand, indicate what these guards would do in response to a violation. Each violators of each category of soldier, noble, civilian, visitor, and hostile could have separate enforcement levels.
-Abscond. The main priority is getting the individual away from the act. Soldiers will order their mark to evacuate the area, and soldiers will attempt to prevent their target from following by persuasion, intimidation, and then submission. Either of the first two steps may be skipped by default for some targets (dumb targets will have persuasion skipped, fearless targets skipping intimidate, etc)
-Submission. Soldiers will immediately attempt to incapacitate those who violate their mark into yielding. A mix of efficient and quick problem ending, and summary corporal punishment. If the mark is crippled enough to be wrestled easily but still refuses to yield, an officer will slap some shackles on them if available.
-Kill. Give the target no quarter.
-Arrest. Like abscond, but the target must agree, submit, or succumb to attempts of arrest, and will be dragged off to jail if they survive the ordeal and do not rout the guards (resisting arrest is dangerous for those who do so).