+1 I would use that.
I have related requests also:
1) When a unit is in Explore mode the "Explore" button should somehow be highlighted to indicate that explore mode is on, and the highlighting should go away when Explore mode is off. Same would be true of the proposed "Patrol" mode. The first time I used Explore mode I couldn't figure out how to turn it off, LOL.
2) An order to make a unit travel back and forth between two points, this would have to have an aggressive or evasive posture for the patrolling unit. If he's evasive, I just want to be able to catch the fact that an enemy is moving through the area. If he's aggressive he should automatically attack any units belonging to players I'm at war with or any wandering monsters.. Maybe on a medium posture he could only attack enemies who's strength is rated at an equal or lower level.
I think I would refer to my proposed item 2 as a "Patrol" mode and Necaradan666's proposal as a "Defend Borders" mode.