Suppose the Bank of Canada were following a 5% NGDP level-path target. And suppose that actual NGDP was on target, and was expected to remain on target in future. And suppose you were Governor, and one of your advisors gives you some important news. Financial markets are in a bubble, so the prices of financial assets are above their fundamental values. And you know your advisor is always right about this sort of thing (just suppose).
You are an economist. You know there are almost always trade-offs. Keeping NGDP on target is important, but so is financial stability. And there are always diminishing marginal benefits to everything. So it seems rational to sacrifice a little NGDP stability to gain some financial stability at the margin. Who knows, you tell yourself, sacrificing a little NGDP stability in the short run might even help NGDP stability in the long run, because it's harder to keep NGDP on target if financial markets are doing silly things like bubbling and bursting.
But you also believe in transparency, so if you depart from your NGDP target temporarily you must announce that you are doing so.
What would you announce?