Board Thread:Speculation House/@comment-14138255-20141031002615/@comment-10380701-20141101045614

I think the more clever Grimm understood that it was just human shenanigans. It's why we didn't see the Goliath stampede happen, and only the dumbass baby Grimm showed up to rain on everyone's parade.

I think they're waiting for a more real, less obvious opportunity.