On AI, the town guard system has been customized to accommodate the Kin System and to promote game balance.
If you perform a criminal action and NPC's or players witness it, they may call the guards on you. NPC's which are at the scene of the crime and catch you stealing, for example, may call the guards on you as well.
Being ‘caught’ is a special type of failed attempt where guards are notified of your failed attempt, and you will be on their ‘candidate list’ for 15 seconds. (standard OSI.)
If no NPC was at the scene of the crime to witness a criminal action, and the players don’t call “Guards!”, you may freely roam the city.
After being slain by an NPC guard, you must lay low for a while (at least a couple minutes) before encountering the same guard again, otherwise it may still attack you even after changing from criminal to innocent. This situation can be avoided in cases where you do not resist your punishment.
Use caution, as certain actions deemed "dangerous" also constitute criminal actions on Angel Island. Throwing an explosive potion or releasing a dangerous pet within city limits are examples of actions considered to be dangerous in this regard.
Britannian Ranger vs Town Guard
While Rangers and Guards both work for Lord British, Rangers attack criminals on sight, while Guards wait to be called by either players or NPCs who witness a criminal action.
On Angel Island, the City of Vesper has no town guards. Instead, the town is occupied by the Militia and is their stronghold. These NPCs will only attack opposing Kin aligned monsters and players.