http://ringsdb.com/find?q=Guarded+ceaselessly+

If you have one copy on a location can you use the action twice (exhausting two rangers and or scouts) in the same phase/turn to reduce the locations threat value by -4?

Cheers.

Yep!

That's cool. I thought as much but wasn't 100%.

Having real trouble with the Black Serpent quest on normal difficulty. The locations have some high threat and nasty travel conditions so my intention was to pin them and negate them with Guarded Ceaselessly and use weak non questing scouts to do the guarding.

Getting just two of the threat four locations out is nasty and of course travelling and exploring them recycles them back. Guarding them ceaselessly might be the trick.