Stealthy units can move without being seen on the strategic map. This allows them to try to infiltrate hostile territories. Patrolling units and the inherent patrol effect from province defense can however discover them. This happens after movement in the Turn Order Sequence, so a hidden commander cannot be caught by patrols in a province they are leaving, but could be caught by patrols in the province they are moving to. If they are caught by patrollers in the province they are moving into, a battle ensues immediately.
This means, in practice, that stealthy units moving around in friendly territory, in battle zones, or on top of sieged forts are safe.
The Hotkey for moving stealthy commanders without sneaking is ctrl + click on a province.
Patrol/stealth calculations
A stealthy commander has a number of interesting uses:
Commanders set on stealthy orders (hide or sneak) are unaffected by:
Commanders set on stealthy orders are still affected by: