As such the consequence of NK's standards of always having some army mobilized and some backup that's ready to go as well.
But it's not like the US is completely in the dark of what's going on. They'll have the DEFCON level upped well before NK does anything completely stupid (meaning faster deployment).
And the amount of bull**** that NK manages to come up with over anything, they're probably using any excuse to chip away at South Korea's defense before they go barging in (what I think they're reason for more aggression). One guy who made a very dangerous tourist visit to NK making a secret documentary showed that the NK side is much more relaxed at how much they can get away with making fun at the SK side of the international border (while SK is much more strict and tells you not to look at the NK solders or make signs and whatnot).
Other's say that they're trying to get more negotiation power for their really bad food aid status.