Those finding themselves inside bubbles (ex post) are always unable to recognise it ex ante. At the practical level, lobbyists, lawyers and enlisted media will be used to sell the idea that “this time it’s different” and that there need be no policy resistance to macroprudential concerns.
A final general concern is that policymakers will commonly have no clear idea of what effect their policy actions might have. In part, this is for the same reasons that cast doubt on whether there is a macroprudential problem in the first place.