Cleric's Liberation Ability for Liberation Domain and Difficult Terrain Question

[Major Doom]

Would the Liberation ability found under the Liberation domain allow a cleric to overcome difficult terrain?

[Master of the Dark Triad]

Yes.

[The Thing from Beyond the Edge]

Is it possible to suppress automatic abilities?
Or, IOW, is it possible to keep this power from activating at each and every instance of difficult terrain?
Otherwise, if said character ventures into a swamp, his uses will probably be gone in less than a minute without ever entering combat and seeing 5' squares.
Or, is difficult terrain a concept that only applies in combat time?